Question

How many numbers greater than 10 and smaller than 25 with distinct digits can we make by using two of the digits 2, 0, 1, and 8 ?

Answer 1

Only four numbers can be formed

Explanation:

We are to make numbers greater than 10 and less than 25

Distinct digits should be there

As such all numbers lying between 10 and 25 are

11,12,.....24

Of these the conditions are only 2, 0, 1 , 8 should be used.

First digit cannot be 0 or 8 because we want two digit numbers between 10 and 25

So first digit can be either 1 or 2

If first digit is 1, second digit can be either 2 or 8 i.e. only 12, 18

If first digit is 2, second digit can be 0 or 1 cannot be 8 i.e. only 20 , 21

Only 4 numbers can be formed