Question

purnima's grandfather is 7 years elder to her grandmother.the sum of one eigth of her grandfather's age and one ninth of her grandfather's age equals 20 years . how old are purnimas grandfather?

Answer 1

Let grandfather's age = x years

Let grandmother's age = y years

x - y = 7

x = 7 + y

x/8 + y/9 = 20

(7+y)/8 + y/9 = 20

On solving you get:

63 + 17y = 1440

17y = 1377

y = 81 years

x = 7 + 81

x = 88 years (Ans.)