Question

The age of A and B are in the ratio 3:5 . After 9 years the ratio of their ages will be 3:4 . The present agr of B is ..?

Answer 1

the present age of B is 20

Answer 2

Answer:

15 years old

Step-by-step explanation:

Ratio now:

• A/B=3/5 => B=5A/3

Ratio after 9 years:

• (A+9)/(B+9)=3/4
• 4(A+9)=3(B+9)
• 4A+36=3B+27
• 4A+9=3B
• 4A+9=3*5A/3     ------  (substitute B with value  from first equation)
• 4A+9=5A
• A=9
• B=5*9/3=15

Answer: the present age of B is 15