math
posted by sylvie on .
The number of boys in a certain class exceed the number of girls by 7. If the number of boys is 5/4 of the number of girls, how many boys are there in the class?
The choices of answers are:
a) 21
b) 28
c) 35
d) 42
e) 63
I figured out that the answer is 35, but I did it by subtracting each of the possible answers by 7 and then multiplying that answer by 5/4.
This is what I did to get my final answer using 35: 35  7 = 28; 5/4 X 28/1 = 140/4 which equals 35.
Now, I know there must be a simplier way to get that answer.
Can you show me step by step? Thanks.

B7=G
B= 5/4 * G = 5G/4
5G/47=G
5G28=4G
G=28
B=28+7=35
G=28 
Thanks very much.