Quantitative Analysis

Question

   Probability of choosing three males from a group of 20 people of which 7 are female.

Answer 1

Write 13/(13+7) times 12/(12+7) times 11/(11+7) or 1716/6840 equal to 0.250877193 (or 0.251).

Also calculate as ₁₃C₃ divided by ₂₀C₃ or 13!/3!/(13-3)! ÷ 20!/3!/(20-3)! which reduces to

(13×12×11)/6 ÷ (20×19×18)/6 or (13×12×11)/(20×19×18) or (13×11)/(30×19) equal to 0.250877193 (or 0.251).