Ana is 4 years older than Ben, and the sum of their ages is 40. How old is Ana?
Correct answer: D. 22
Let Ben be x and Ana x + 4: 2x + 4 = 40, so x = 18 and Ana is 22. Shortcut: half of (sum + difference) gives the larger number, (40 + 4) ÷ 2 = 22.
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