A) 1560
B) 840
C) 1080
D) 480
Correct Answer: A
Solution :
There can be 2 types of numbers. (i) Any one of the digits 1,2,3,4 repeats thrice and .the remaining digits only once i.e., of the type 1, 2, 3, 4, 4, 4. (ii) Any two of the digits 1,2,3,4 repeat twice and the remaining two only once i.e.,of the type 1, 2, 3, 3, 4, 4. Number of numbers of the type 1 2 3 4 4 4 \[=\frac{6!}{3!}{{\times }^{4}}{{C}_{1}}=480\] Number of numbers of the type 1 2 3 3 4 4 \[=\frac{6!}{2!2!}{{\times }^{4}}{{C}_{2}}=1080\] So, the required number = 480 + 1080 = 1560
You need to login to perform this action.
You will be redirected in
3 sec
