number of candidates who answer ten questions is equal to the number of candidates who answer nine questions only. Find the probability that a candidate chosen at random from among these two sets of candidates will have selected questions 1, 2 and 3 if all the questions have the same chance of being selected. (the question had been answered in the same website but I couldn't understand the solving way..please help)

number of candidates who answer ten questions is equal to the number of candidates who answer nine questions only. Find the probability that a candidate chosen at random from among these two sets of candidates will have selected questions 1, 2 and 3 if all the questions have the same chance of being selected. (the question had been answered in the same website but I couldn't understand the solving way..please help)

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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