The sum of three consecutive odd numbers is 20 more than the first of these numbers. What is the middle number?
Answers:
A) 3  B) 6  C) 9  D) 12  E) 15
Sol.   Let the numbers be x, x + 2 and x + 4.   Then, x + (x + 2) + (x + 4) = x + 20 ⇔ 2x = 14 ⇔ x = 7.   ∴ Middle number = x + 2 = 9.   Answer 9
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The sum of three consecutive odd numbers is 20 more than the first of these numbers. What is the middle number?