Question 604485
Letty's age = L
Cory's age = C
Ben's age = B


L = 10 + C
C = 1/2 * B
so B = 2C


L + C + B = 54
10 + C + C + 2C = 54
10 + 4C = 54
4C = 54 - 10
4C = 44
C = 44/4 = 11


L = 10 + C = 10 + 11 = 21
B = 2C = 2*11 = 22


so, Ben is 22 years old