The ratio of boys to girls is 3 to 7. If there are 200 more girls than boys how many boys were enrolled that year?

Question

In 2012 the ratio of boys to girls was 3 to 7. If there are 200 more girls than boys in 2012 how many boys enrolled that year?

Answer 1

Since the ratio of boys to girls is 3 to 7, the difference between them is 200.  The ratio difference is 4, so the 200 divided by 4 equals 50.

 

So, there are 3 * 50 = 150 boys.

There are 7 * 50 = 350 girls.

 

When you check, a ratio of 150:350 = 3:7 and the number of girls (350) is 200 more than the number of boys (150).

 

Hope this helps, Bridget.

 

Mary Ann

Answer 2

First sentence, describing girls in terms of boys - 

 

g = b * 7/3

 

Second sentence, describing girls in terms of boys -

 

g = b + 200

 

 

Using the two sentences together, describing boys in terms of boys - 

 

b * 7/3 = b + 200

 

then subtracting b from each side and solving for b

 

b * 4/3 = 200

 

b = 200 * 3/4

 

b = 150

 

And substituting into the first equation

 

g = 150 * 7/3 = 50 * 7 = 350

 

And substituting into the second equation to check the answer 

 

g = 150 + 200 = 350 check