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← JEE Main 2015 · 10 Apr · Shift 1
MathematicsSingle correct+4 / -1Question 66 of 90

JEE Main 2015 · 10 Apr · Shift 1, Mathematics question 66

The number of ways of selecting 15 teams from 15 men and 15 women, such that each team consists of a man and a woman, is :

Choose one option
Answer and worked solution

Official answer: B

The question does not pin down what is being counted: pairing all 15 men with distinct women gives 15!15!, and choosing a single man-woman team gives 225. Neither is an option.

The keyed value, 1240, equals ∑k=115k2=15⋅16⋅316\sum_{k=1}^{15}k^2=\dfrac{15\cdot16\cdot31}6; no reading of the wording that we could find leads to it directly. The answer follows the official key.