Question

the ratio of the ages a and b is 4:5 respectively. the ratio of their ages 3 years ago was 5:7. how old is b​

Answer 1

Answer:

According to the given condition

» a/b = 4/5

» 5a - 4b = 0 ... (1)

According to the second condition

» (a - 3)/(b - 3) = 5/7

» 7a - 21 = 5b - 15

» 7a - 5b = 6 ... (2)

Multiply eq (1) by 5 and eq (2) by 4

» 25a - 20b = 0 ... (3)

» 28a - 20b = 24 ... (4)

» a = 24/3 = 8

& b = 10

Therefore, the age of b is 10 years.