Answer:
larry is 19
Explanation:
ok, so larry's age is y, his sisters age is x
x + 8 = y
thats the equation for him being 8 years older
now 2y = 3x + 5
his sisters age is 3x + 5 to get larry's age when its doubled
substitute x + 8 in for y
2 (x+8) = 3x + 5
2x + 16 = 3x + 5
16 = x + 5
x = 11
11 + 8 = y
y = 19