Sunday, May 20, 2007

Interesting Maths Problem

I just encountered an interesting maths problem which I would like to share.

There are three classes in a school, each with the same number of students. The fraction of girls in class A is the same as the fraction of boys in class C. Also, class B has one-fifth of all the boys in the school.

What is the fraction of girls in the school ?

For your info, this question is a Sec One question. Frankly, I'm quite surprised at this fact. In anycase, I didn't use algebra to solve this problem - that felt unfair. Anyway intuition should prove helpful in tackling this question.

4 comments:

Anonymous said...

The answer is 1r4r5 / 3 = 9/5 / 3
It is 3/5. Not extremely hard question. Just out of the box.

The Negative Man said...

Unfortunately your answer is wrong.

zhenxi said...

hah. 7/12 lah. =X

I know I already got it wrong. =(

The Negative Man said...

Yes the answer is 7/12.

Yay !