1
WB JEE 2023
MCQ (More than One Correct Answer)
+2
-0
Change Language

A letter lock consists of three rings with 15 different letters. If N denotes the number of ways in which it is possible to make unsuccessful attempts to open the lock, then

A
482 divides N
B
N is the product of two distinct prime numbers.
C
N is the product of three distinct prime numbers.
D
16 divides N.
2
WB JEE 2018
MCQ (More than One Correct Answer)
+2
-0
Change Language
On the occasion of Dipawali festival each student of a class sends greeting cards to others. If there are 20 students in the class, the number of cards sends by students is
A
$${}^{20}{C_2}$$
B
$${}^{20}{P_2}$$
C
$$2 \times {}^{20}{C_2}$$
D
$$2 \times {}^{20}{P_2}$$
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