CBSE Class 11-science Answered

Solutions

Total numbers that can be formed using these digits are

One digits numbers = 5

Two digits numbers 25

Three digits number =125

Four digits number = 625

Five digits number = 3125

So total numbers = 3905

Case 1 when digits can repeat them selves the four digit even numbers can be

5*5*5*2 =250 numbers

So probability of getting an even numbers = 250/3905 = 50/781

Case 2 when repetition is not allowed  

Number of 4 digit numbers

4*3*2*2 = 48 such numbers

Probability = 48/3905

Case 3

The possible numbers could be 8752 , 8521 ,8751,8752,8721,7521.

So the probability is  6/3905