29.How many 3-digit numbers can be formed from the digits 2, 3, 5, 6, 7 and 9 which are divisible by 5 and none of the digits is repeated?
A. 5 B. 10
C. 15 D. 20
Answer:
Since each desired number is divisible by 5, so we must have 5 at the unit place. So, there is 1 way of doing it.
Tens place can be filled by any of the remaining 5 numbers.
So, there are 5 ways of filling the tens place.
The hundreds place can now be filled by any one of the remaining 4 digits. So there are 4 ways of filling it.
Required number of numbers(1x5x4) = 20.
