Question

2 3 5 8 7 by using these five numbers how many 3 digit number can be formed which are divisible by 2

Answer 1

Answer:

Step-by-step explanation:

As 3 digit number is divisible by 5, its unit place should contain digits 0 or 5. As you can see we have only 5 present here, put it in units place. Now you have 5 digits - 2, 3, 6, 7, 9 remaining.

So you can select 5 digits for tens place and as repeatation is not allowed, for hundreds place you can select remaining 4 digits. So final answer is 4 * 5 * 1 = 20 numbers can be formed.

OR

You can select 2 digits out of 5 digits given in C(5,2) = 20 ways. And as units place contain only 5, final answer becomes 20 * 1 = 20.