Maths Problem

katiewobbles

Would appreciate any help on the mahs problem below. Asked my friends and we can't get the same answer...


The picture shown below is to be colored in.
(http://i254.photobucket.com/albums/hh94/katiewobbles/Teammaths98permutation.jpg)
Five different colours are available. Each region is to be a single colour and no two adjacent regions are to be the same colour. How many different versions are possible?

kaki

The way I'd look at it is that it's a sky, a sun, a road and two fields.

Take the sun: it can be coloured in 5 different ways.
The sky: Can be coloured in 4 ways (must not be same as sun)
The path: Can be coloured in 4 ways (must not clash with sky)
The left field: Can be coloured in 3 ways (mustn't clash with sky or path)
The right field: Can be coloured in 3 ways (mustn't clash with sky or path)

Then I think you just multiply the number of possibilites for each section together: 5x4x4x3x3=720...I think. Am totally open to correction though

katiewobbles

Thats EXACTLY how i did it!
I only had doubts because it was a different answer to that of a girl who's a super genius at maths and i didn't understand her way so i had hoped that someone else could back up my version or make the other version clearer.
Thanks btw!

katiewobbles

Problem No.2:
A circle has both the X-axis and the Y-axis as tangents. Its centre lies on the segment from (0,10) to (15,0). Find its equation.

Would appreciate any help:)

katiewobbles

Solved the last question on the circle, that's fine
:)

sd123

katiewobbles wrote: »

Problem No.2:
A circle has both the X-axis and the Y-axis as tangents. Its centre lies on the segment from (0,10) to (15,0). Find its equation.

Would appreciate any help:)

Just had a quick look at this one, my maths is getting a bit rusty though.

let centre of circle be (-h,-k), h = r = k

equation on line passing between (15,0) and (0,10) => 2x+3y-30=0 , centre of circle, (-h,-k) is an element of this line. but we know that h=k, therefore, h = -6 and y = -6.

eqtn of circle = (x -h)^2 + (y-k)^2 = r^2

r= -6

I got x^2 + y^2 +12x - 12y +36 = 0

Some of those equations could be wrong, I haven't done maths in over 9months... hope its right

conzy

The Circle is a horrible question