Question 732837
Let Percy's age be p
Let Ginny's age be g


Percy is 8 years older than Ginny
g + 8  = p -----------------------eq. 1


In ten years time he will be three times Ginny's present age

In ten years Percy will be p + 10 yrs old
Three times Ginny's age = 3g
p + 10 = 3g --------------eq 2


Substitue eq1 in eq2
p + 10 = 3g
g + 8 + 10 = 3g
g + 18 = 3g
2g = 18


g = 9


Ginny's age is 9 years

Substitute g = 9 in eq 1


g + 8  = p
9 + 8 = p


P = 17