Question

║⊕QUESTION⊕║
LITTLE HELP MY UNKNOWN USERS !!!!!!!!!
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CLASS 11
PERMUTATIONS AND COMBINATIONS
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How many 4 digit numbers can be formed by using the digits 0, 1, 4, 5, 7, 9 if
a) the repetition of digits is not allowed.
b) the repetition of digits is allowed.

Answer 1

Answer:

a)

6P4=6!/(6-3)!

=6x5x4

=120

b)

6x6x6x6=1296

Answer 2

Step-by-step explanation:

We can only choose one out of 5 digits for 1st selection as we can not start with zero .

Please find the solution in attachment .