***** Leaving Cert Ordinary Level Maths - both papers ****

smtp95

martmikey wrote: »

Could someone please tell me how to do this question:

Helen has enough credit to download three songs from the internet. There are seven songs
that she wants.

(i) How many different possible selections of three songs can she make?


(ii) If there is one particular song that she definitely wants, how many different selections
can she now make?

PLEASE

For part (i) she can buy 3 but there are seven choices. So imagine you have 3 boxes for the songs she can buy. For the first box she has seven choices, for the second she has six and for the third she has five. 7X6X5= 210 different selections

For part (ii). Imagine one of those 3 boxes for the songs is filled, you only have one choice there. So in the second box you will now have 6 possible choices and for the third you will have five. 1X6X5=30 selections

I hope this helps. If you have Active Maths they cover this chapter very well in the book

Troxck

martmikey wrote: »

Could someone please tell me how to do this question:

Helen has enough credit to download three songs from the internet. There are seven songs
that she wants.

(i) How many different possible selections of three songs can she make?


(ii) If there is one particular song that she definitely wants, how many different selections
can she now make?

PLEASE

Use the nCr function on your calculator!

(i) How many ways can she pick 3 songs from 7 songs?

7C3 which is 35.

(ii)She picks a song she particularly likes. Put that aside. She now is left with picking 2 songs from 6
songs.

So it is 6C2 which is 15.

I hope this helps!

hontheroyalz

martmikey wrote: »

Could someone please tell me how to do this question:

Helen has enough credit to download three songs from the internet. There are seven songs
that she wants.

(i) How many different possible selections of three songs can she make?


(ii) If there is one particular song that she definitely wants, how many different selections
can she now make?

PLEASE

I might be wrong but heres my answer:

(i) she can download 3 songs, with 7 options..therefore 7x6x5 as one song is taken out each time

(ii) this time it's 1x6x5 as you have to have one for sure, again multiplying by the remaining songs

martmikey

smtp95 wrote: »

For part (i) she can buy 3 but there are seven choices. So imagine you have 3 boxes for the songs she can buy. For the first box she has seven choices, for the second she has six and for the third she has five. 7X6X5= 210 different selections

For part (ii). Imagine one of those 3 boxes for the songs is filled, you only have one choice there. So in the second box you will now have 6 possible choices and for the third you will have five. 1X6X5=30 selections

I hope this helps. If you have Active Maths they cover this chapter very well in the book

Thanks... Thats what i thought but when i looked up the marking scheme.. This was the answer:

How many different possible selections of three songs can she make?

= 35



(ii) If there is one particular song that she definitely wants, how many different selections
can she now make?

= 15

Aarong9224

FlyingIrishMan wrote: »

I got a markup of around 75% too.

The total he made from selling 22 sets at normal prices + the 3 remaining sets discounted at 20% was around 2100. And then I just got the percentage difference between the original 1250 and the new total with the discounted sets.

I also got that , maybe we were right

zvseire wrote: »

i guessed d anybody know the correct answer?

Correct answer was D

smtp95

martmikey wrote: »

Thanks... Thats what i thought but when i looked up the marking scheme.. This was the answer:

How many different possible selections of three songs can she make?

= 35




(ii) If there is one particular song that she definitely wants, how many different selections
can she now make?

= 15

Hmmm... :P

I think we're right because with seven choices and three possible songs there would be a lot of possible combinations, not just 35.

But if that's what the marking scheme says well... Damn permutations

aleatorio

smtp95 wrote: »

Hmmm... :P

I think we're right because with seven choices and three possible songs there would be a lot of possible combinations, not just 35.

But if that's what the marking scheme says well... Damn permutations

HL student here,
It's because the 210 combinations are including the different orders of the songs, as in 1,2,3 and 3,1,2 - they're the same songs downloaded, just a different order, so 210 is not correct

The correct answer is 35 because 7choose3 is
7! Divided by 3!((7-3)!)
The formula for nchooser is n!/(r!((n-r)!)
Which gives 35

Then for the second part, it's 6choose2 because one has already been chosen, which using the above formula gives 15

smtp95

aleatorio wrote: »

HL student here,
It's because the 210 combinations are including the different orders of the songs, as in 1,2,3 and 3,1,2 - they're the same songs downloaded, just a different order, so 210 is not correct

The correct answer is 35 because 7choose3 is
7! Divided by 3!((7-3)!)
The formula for nchooser is n!/(r!((n-r)!)
Which gives 35

Then for the second part, it's 6choose2 because one has already been chosen, which using the above formula gives 15

Ahh alright, I get it now. Thanks. That's what I do OL for :P

coffeelover95

Dee15 wrote: »

Just realised I forgot to write in my calculator information on the front of the paper, is that important?!

I forgot too! I asked my maths teacher though and she said it was okay so don't worry about it

Rainydays212

Do you think they will give us an easier paper two? So nervous for Monday..:/

onethreefive

Rainydays212 wrote: »

Do you think they will give us an easier paper two? So nervous for Monday..:/

My future is relying on the hope that it will be easier..

Rainydays212

onethreefive wrote: »

My future is relying on the hope that it will be easier..

Me too !!!! Oh lord..why do they do this to us

miissjuly

Guys I just checked the answers got around a B on Paper 1 so hopefully I can get an A with paper 2. As if 60/50 points is going get me 550 points.. *sighs*

neonmaria

im really worried about probability and trigonometry
i used to like trigonometry but the way its done in project maths i hate it

jazz101

miissjuly wrote: »

Guys I just checked the answers got around a B on Paper 1 so hopefully I can get an A with paper 2. As if 60/50 points is going get me 550 points.. *sighs*

Where did you check the answers?

onethreefive

I want to cover as many topics as I can tomorrow. What exactly should I cover in order of importance for paper 2?

RAnderson1995

miissjuly wrote: »

Guys I just checked the answers got around a B on Paper 1 so hopefully I can get an A with paper 2. As if 60/50 points is going get me 550 points.. *sighs*

where did you get the answers?

miissjuly

I cannot post images or URLs because I am new user (?) been using more than a year thanks boards!! I could send you all as a message if you want?

kev44

miissjuly wrote: »

Guys I just checked the answers got around a B on Paper 1 so hopefully I can get an A with paper 2. As if 60/50 points is going get me 550 points.. *sighs*

Can you type the url?

delaad

smtp95 wrote: »

Ahh alright, I get it now. Thanks. That's what I do OL for :P

Pretty certain combinations were dropped from the course 2/3 years ago.

randylonghorn

miissjuly wrote: »

I cannot post images or URLs because I am new user (?) been using more than a year thanks boards!!

Unfortunately, because of some REALLY disturbing stuff spammed on to Boards a couple of months back by someone who kept creating new accounts to do so, a restriction was introduced that images etc. couldn't be posted by a user with less than 50 posts and a months use of Boards (if I remember the details correctly).

Unfortunately, it does sometimes catch genuine posters as well.

jazz101

How disturbing are we talking Randy? I'm a curious kind of guy.

randylonghorn

jazz101 wrote: »

How disturbing are we talking Randy? I'm a curious kind of guy.

Very, jazz, and I'm not exactly the most easily shocked.

bradlente

There are solutions online on the official exam paper site for one of the exam papers,Does anyone know if there are more solutions available for the other ones on another site?Handy to see exactly how they're done.

sienna_xo

This probably sounds really stupid, but what is everyone studying for Paper 2?

I feel so unprepared for P2 in comparison to P1.

HauntedGhost

I made a good attempt at nearly every question bar the last one, would that be enough to pass? Obviously I did get a few of the parts a and b right!

gal555

Just lots and lot of shapes and **** :L
Well like Geometry and then statistics and probability

onethreefive

I can't figure out how to construct the incircle of a triangle This book makes no sense

Osmosis Jones

onethreefive wrote: »

I can't figure out how to construct the incircle of a triangle This book makes no sense

Bisect two angles, where the bisector lines cross is the centre of the circle.

onethreefive

Osmosis Jones wrote: »

Bisect two angles, where the bisector lines cross is the centre of the circle.

Without trying to sound stupid where do I place the sharp part of the compass to bisect an angle?

Osmosis Jones

onethreefive wrote: »

Without trying to sound stupid where do I place the sharp part of the compass to bisect an angle?

Place it on the corner of the angle, mark off a point on each of the two sides that make up the angle, make sure the points are of equal distance. Then place your compass on each of these points and draw an arc. Where these two arcs meet, draw a line from the corner of the triangle through the point made by the arcs.

sienna_xo

It's really sad that I'm dreading my only OL subject more than the six that I'm sitting at HL.

But anyway, hopefully this is the last Maths exam that I (and everyone like myself) ever have to do!

miissjuly

The constructions on mathopenref are really good you all should watch them.

neonmaria

anyone know where I can get a solution to paper 1 ?

A7XGirl

neonmaria wrote: »

anyone know where I can get a solution to paper 1 ?

http://www.leavingandjuniorcertanswers.org
It's the second pdf

miissjuly

You can find the answers to paper one on leavingcertpredictions . com

neonmaria

thanks so much been looking everywhere for it although after looking at that solution I feel sick

onethreefive

How do I get my calculator of radien mode Its a casio one

RAnderson1995

I have a terrible feeling that if i look at the answers i'm going to want to cry ...

gal555

I don't get the point in looking at them anyway!...
Just get in the mindset for paper two without stressing about what cant be changed

HauntedGhost

What should I concentrate most on for paper 2?

RAnderson1995

not as bad as i thought on paper 1!!
have the whole course for paper 2 studied, feeling confident!

jazz101

A7XGirl wrote: »

http://www.leavingandjuniorcertanswers.org
It's the second pdf

RAnderson1995 wrote: »

I have a terrible feeling that if i look at the answers i'm going to want to cry ...

It's certainly made me pessimistic.

miissjuly

HauntedGhost wrote: »

What should I concentrate most on for paper 2?

If you go over these you will be sorted
Probability
Statistics
Co-ordinate geometry of the line and circle
Trapezoidal rule
Theorems/proofs (I don't know if you have to prove anything for ordinary level)
Know your Constructions
Trigonometry

Well that's everything really.

LoveLamps

What do I need to KNOW for tomorrow?
Im grand and can do all the sums on probablility, co ordinate geometry etc etc but what do I actually have to learn?
The unit circle? The constructions? That it??

RAnderson1995

jazz101 wrote: »

It's certainly made me pessimistic.

Made me more Optimistic!

miissjuly

scareyc wrote: »

Im in the same boat as you, just want to pass. I got 38% in the mocks which is a fail. 40% is a pass, but some say that if you're at 38% they'll boost you up to a pass. Im just gonna completely cram paper 2 this weekend and hope to raise my grade..

Do you ever get that feeling of regret? How is 38% considered a pass? All I heard was that this year they are going to review project maths so they don't many failing and if you get around 38/39% they will try to look for marks or mark easier so you could just pass. If I knew that 38/39% would be considered as passing I would have taken the risk. I feel horrible now. There were some parts in the ordinary level paper I thought was ridiculously easy and some project maths element was tricker but not as much as higher level. I had two mocks one I failed by 1% and the other I passed yet I took the OL paper. I know people that are just like me but stuck to HL and might just pass get the 70 points and I'm badly in need of points. I feel dumb and angry at myself I should die under a bus! Many of you won't be counting ordinary maths while I will be.. arghh

hontheroyalz

In state exams if you get 38% or higher the computer automatically counts it as a pass..fact

miissjuly

hontheroyalz wrote: »

In state exams if you get 38% or higher the computer automatically counts it as a pass..fact

Fabulous 70 points gone! Never going to college. Hurray!

onethreefive

Is this correct?

Mean: = The number which appears the most

Median = Put them in order from lowest to highest and get the middle number

Mode = Add up all the numbers and divide by the amount of numbers.