Sam and Drew have a combined age of 54. Sam is half of Drew's age. How old is Sam?
Let's be accurate as possible and think first.
18
Let x be Drew's age.

Sam is (1 / 2)x.

x + (1 / 2)x = 54.

(3 / 2)x = 54.

3x = 108.

x = 36.

Sam is 36 / 2 = 18 years old.

.

The final answer: 18