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Free GMAT Problem Solving Practice Question

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A media company assigns its 30 editors to exactly three desks: News, Features, and Sports. Last quarter, News editors published an average of 30 articles each, Features editors an average of 60 each, and Sports editors an average of 90 each, and the average across all 30 editors was exactly 50. If each desk has at least one editor, what is the greatest possible number of editors assigned to the Sports desk?

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Answer & Explanation

Correct answer

D

Let the News, Features, and Sports counts be a, b, and g. There are two constraints: a + b + g = 30 editors, and 30a + 60b + 90g = 50 × 30 = 1,500 articles. Dividing the article equation by 30 gives a + 2b + 3g = 50.

Subtract the count equation from this to eliminate a: (a + 2b + 3g) − (a + b + g) = 50 − 30, so b + 2g = 20, giving b = 20 − 2g. Substituting back, a = 30 − b − g = 30 − (20 − 2g) − g = g + 10.

The reflex to minimize every other desk in order to maximize Sports is the trap here. Since a = g + 10, News grows as Sports grows and cannot be minimized; the only count free to shrink is Features, b = 20 − 2g. So the binding floor is Features ≥ 1. From 20 − 2g ≥ 1 we get 2g ≤ 19, so g ≤ 9.5, and since g is a whole number, g ≤ 9. At g = 9, Features = 2 and News = 19, and 19 + 2 + 9 = 30 with (30 × 19 + 60 × 2 + 90 × 9) ÷ 30 = 1,500 ÷ 30 = 50. So the greatest possible Sports count is 9, and the answer is D.

(A) 6, (B) 7, and (C) 8 are all feasible splits (News 16/17/18, Features 8/6/4), so any trial-and-stop approach lands on one of them; only pushing Features down to its floor of 2 reveals the true maximum. (E) 10 drops the at-least-one floor on Features (or assumes an equal 10-10-10 split, or rounds 9.5 up), which is the dominant trap. A two-desk alligation lever does not apply with three desks, and the choices cannot simply be plugged in without first deriving b = 20 − 2g and a = g + 10, so the system reduction plus the integer floor is unavoidable.