Question

There are 3 times as many males as females on the maths course at university. What fraction of the course are male?

Answer 1

(1)

If there are three times as many males as females, the ratio of males to females would be 3:1.

To make this more clearer. Suppose you have 100 students. for each 4 students, 3 of them are male and 1 is a female.

We can then say there are 75 males and 25 females.

Expressing this as a ratio(fraction) is easy 3 out of 4 are males and 1 out of 4 are females. So the ratio of males would be;

$r(m) = \frac{3}{4}$

(2)

Let x be the number of cola bottles

Let y be the number of smarties

Let z be the number of marshmallows

x=3y (since there are 3 times more x than y)

y=2z (since there are 2 times more y than z)

we know that marshmallows are twice as less as smarties. so for 1 marshmallow you'd have 2 smarties. But we also know that cola bottles should be 2×3=6 since we have 3 times more cola bottles than smarties.

Adding up our total sweets we get;

1+2+6=9

But how many of those are cola bottles? 6!

So the ratio of cola bottles can be expressed as,

$r(c) = \frac{6}{9} = \frac{2}{3}$

You can simplify the numerator and denominator by 3 to get 2 over 3.