Question

The ratio of boys to girls in Class A is 3 to 4. The ratio of boys to girls in Class B is 4 to 5. If the two classes were combined, the ratio of boys to girls in the combined class would be 17 to 22. If Class A has one more boy and two more girls than class B, how many girls are in Class A?

Answer 1

Explanation:

Let B be number of boys present in Class A

Let G be number of girls present in Class B

B/G= 3/4 ---> 4B-3G=0 (1)

For class B

B-1 / G-2 =4/5

5(B-1)=4(G-2)

5B -4G=-3 (2)

Solving equation 1 and 2

20B -15G=0

20B-16G=-12

G=12

Number of girls in class A is 12