Question

How many 5 digit numbers divisible by 5 can be formed using 0,1,2,3,4,5 if repeatition not allowed.

a)" "220

b)" "240

c)" "None

Solution

Since repeatition not allowed so we can use a number only once.For number to be divisible by 5, its unit place must have either 0 or 5.

Case 1

Lets fix 0 at unit place the we can arrange rest digits in the form of 5xx4xx3xx2 = 120

Case 2

Now if we will 5 at unit place, we can arrange rest numbers as 4xx4xx3xx2 = 96

Hence total numbers = 120 + 96 = 216