NIMCET 2020 Mathematics PYQ — 6 Naresh has 10 friends, and he wants to invite 6 of them to a pa… | Mathem Solvex | Mathem Solvex
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NIMCET 2020 — Mathematics PYQ
NIMCET | Mathematics | 2020
6 Naresh has 10 friends, and he wants to invite 6 of them to a party. How many times will 3 particular friends never attend the party?
Choose the correct answer:
A.
8
B.
7
(Correct Answer)
C.
720
D.
35
Correct Answer:
7
Explanation
Concept: nCr=r!(n−r)!n! Calculations: Given, Naresh has 10 friends, and he wants to invite 6 of them to a party. Remove the 3 particular friends and invite 6 friends from the remaining = 10 - 3 = 7 friends. This can be done in 7C6 ways Hence, required number of ways = 7C6 ⇒ required number of ways =(7−6)!6!7! ⇒ required number of ways =7 Hence, Naresh has 10 friends, and he wants to invite 6 of them to a party. total number of ways that 3 particular friends never attend the party = 7
Explanation
Concept: nCr=r!(n−r)!n! Calculations: Given, Naresh has 10 friends, and he wants to invite 6 of them to a party. Remove the 3 particular friends and invite 6 friends from the remaining = 10 - 3 = 7 friends. This can be done in 7C6 ways Hence, required number of ways = 7C6 ⇒ required number of ways =(7−6)!6!7! ⇒ required number of ways =7 Hence, Naresh has 10 friends, and he wants to invite 6 of them to a party. total number of ways that 3 particular friends never attend the party = 7