Question

Numbers 64 and 36 have the property that they are divisible by their unit's digit. The number of numbers between 20 and 60 such that this property is satisfied by them is:
1. 19
2. 21
3. 20
4. 17

Answer 1

Correct Answer - Option 4 : 17

Calculation:

Number ending with 1 = 21, 31, 41, 51 = 4 are divisible by 1.

Number ending with 2 = 22, 32, 42, 52 = 4 are divisible by 2.

Number ending with 3 = 33 is divisible by 3.

Number ending with 4 = 24, 44 = 2 are divisible by 4.

Number ending with 5 = 25, 35, 45, 55 = 4 are divisible by 5.

Number ending with 6 = 36 is divisible by 6.

Number ending with 8 = 48 is divisible by 8.

Number ending with 9 or 7 are not divisible by 9  or 7 respectively.

∴ Total such number which satisfy this property = 4 + 4 + 1 + 2 + 4 + 1 + 1 = 17

 We cannont devide any number by 0. As, the result of any number divided by 0 is undefined.