Help with a problem...

Keyzer

Can someone solve this for me please? I know its not quantum physics but I'm getting conflicting answers from different solution sites and I want to make sure I have the right answer:

Yakuza

Look up BOMDAS - Brackets, orders, multiplication, division, addition, subtraction

Starting with [latex]\left(\frac{\frac{2}{3}+\frac{1}{2}}{\frac{2}{5}}\right) \times 2 - 6 \div 3[/latex]
Express the fraction to be summed as a single fraction, the common divisor is 6. Also, [latex]6 \div 3[/latex] reduces to 2:

We now have: [latex]\left(\frac{\frac{4}{6}+\frac{3}{6}}{\frac{2}5}}\right) \times 2 - 2[/latex]

add the fractions:[latex]\left(\frac{\frac{7}{6}}{\frac{2}{5}}\right) \times 2 - 2[/latex]

When dividing by a faction, turn it upside down and multiply:[latex]\left(\frac{7}{6} \times \frac{5}{2} \right) \times 2 - 2[/latex]

Multiply out the factions, and bring in the multiplier of 2: [latex]\left(\frac{70}{12} \right) - 2[/latex]

Simplify, and express the -2 in 6ths: [latex]\frac{35}{6} - \frac{12}{6}[/latex]

Simplify again: [latex]\frac{23}{6}[/latex]

Keyzer

Thanks - that's the answer I had but some of the online calculators are giving me conflicting answers.

Yakuza

Some of those calculators are very sensitive to how you input the problem, sometimes the best way is pen and paper

Keyzer

one more for you, just to humour me...

locum-motion

Keyzer wrote: »

one more for you, just to humour me...

I got that one as far as 5,339 / 4,680

I'm sure that it could be simplified further by finding the highest common factor of 5,339 and 4,680.

But I'm not gonna try.

Other than brute-forcing it in Excel or some other 'trial-and-error' method, how do you find a HCF?

Yakuza

Keyzer wrote: »

one more for you, just to humour me...

Post your answer, and I'll see if I get the same one. Express the 31/5 - 5/8 as fortieths and the 5/4 and 4/6 as twelfths and continue from there.

Edit: I got a slightly different numerator to locum-motion, the same denominator.

Keyzer

5359 / 4680

Yakuza

That's what I got too, for what it's worth

Keyzer

Thank you, bloody pain in the neck that I can't get the answers from past exam papers from the lecturer.

locum-motion

locum-motion wrote: »

... 5,339 / 4,680
...

Yakuza wrote: »

... I got a slightly different numerator to locum-motion, the same denominator.

Keyzer wrote: »

5359 / 4680

Actually, I've just been to the bin to dig out the envelope I worked on the back of.
I got 5,359 too. I just typed it wrong!

locum-motion

locum-motion wrote: »

...
I'm sure that it could be simplified further by finding the highest common factor of 5,339 and 4,680...

Should I have said "lowest common denominator" there, not HCF?

Ciaran

locum-motion wrote: »

Other than brute-forcing it in Excel or some other 'trial-and-error' method, how do you find a HCF?

Break each number down to its prime factors and see which ones are common to both numbers.