Question

Sue and Fred have a combined age of 42 years. If Sue's age is 1/2 of Fred's, how old is Fred in years?

16
20
23
28
35

Answer 1

sue's age = S
fred's age = F
S + F = 42
S = (1/2)F
substitute for S
(1/2)F + (1)F = 42
(3/2)F = 42 multiply both sides by 2/3
(2/3)(3/2)F = 42(2/3); F = 42(2/3) = 14(2) = 28
S + 28 = 42
S = 42 - 28 = 14
Look back at the problem to see what they are asking.
Fred is 28