Question

A school has a ratio three girls to every five boys if the school has 24 students how many of them are girls

Answer 1

The explanation is much longer than doing the mathematics. The ratio of 15 boys to 10 girls is equivalent to the ratio of 3:2

Explanation:

Consider the starting point:

We have 3 boys and 2 girls. This gives a total count of 5. So, we need to see how many lots of 5 will fit into 25.

5 lots of 5 gives 25

So we have 5 lots of the ratio 3:2

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Method 1

5 lots of 3:2 → 5 x (3:2)=(5 x 3) : (5 x 2) 15:10

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Method 2

Write the ratio in fractional form. We can do this as long as we do not view and treat it like a fraction

It does not matter in this case which we put on the top. I chose:

boys/girls → 3/2

Multiply a value (or system) by 1 and you do not change the value. However, 1 comes in many forms.

3/2 ×1 → 3/2 × 5/ 5 = 3 × 5

---------- =15/ 10 = boys

2 × 5 --------

girls

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The ratio of 15 boys to 10 girls is equivalent to the ratio of 3:2

15:10 = (15 divided by 5) : (10 divided by 5) = 3:2

where (=)- means equivalent to

Answer 2

9 girls

Step-by-step explanation

3x+5x=24

8x=24

x=3

Now go back and replace x with 3

3(3)+5(3)=24

9+15= 24

9 girls is your answer!