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Quantitative Reasoning – Practice – A reading list question!

PSA_LEVEL-UP_QNR5). A reading list for a humanities course consists of 10 books, of which 4 are biographies and the rest are novels. Each student is required to read a selection of 4 books from the list, including 2 or more biographies. How many selections of 4 books satisfy the requirements?

A 90
B 115
C 130
D 144
E 195

Ans: Student can read 2 biographies and 2 novels:

Number of ways to do this= 4c2 * 6c2 = 6 * 15 = 90

Student can read 3 biographies and 1 novels:

Number of ways to do this= 4c3 * 6c1 = 4 * 6 = 24

Student can read 4 biographies and no novels:

Number of ways to do this= 4c4 = 1

Total number of ways = 90 + 24 + 1 = 115. Option B.

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