A selection committee is to be chosen consisting of 5 ex-technicians. Now there are 12 representatives from four zones. It has further been decided that if Mr. X is selected, Y and Z will not be selected and vice-versa. In how many ways it can be done?
A. 572
B. 672
C. 472
D. 372
Answer: Option B
Solution(By Examveda Team)
10C5 : when both are not included. 10C4 : when one of them is included. Number of ways= 10C5 + 10C4 + 10C4
= 672
This Question Belongs to Arithmetic Ability >> Permutation And Combination
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Comments ( 2 )
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Wrong ans. The ans should be
9C5 + ( 9C4 × 3) = 504.
Or, cut the (and Z) portion to meet the given answer.
I didn't understand the solution. Can anyone briefly solve the problem.