Answer:
let the age of elder sister = x+8
then let the age of younger sister be x
sum of their ages = 64
according to the question,
x+8+x = 64
2x+8 = 64
2x = 64-8
2x = 56
x = 56/ 2
x = 28
so, the age of younger sister is 28 years
and the age of elder sister is x+8= 28+8= 36years