Question

The unit's digit of a two -digit number is one more than the digit at ten's place. If the number is more than five times of the sum of the digits of the number, then find the sum of all such possible numbers.

• A. 246
• B. 275
• C. 290
• D. 301

Answer 1

The correct option is C 290

Let the digit at ten's place =x
Digit at unit's place =x+1
5 times sum of digit =5(x+x+1)
=10x+5
The number has to be greater than (10x+5)
Also, x can take values from 1 to 8 only.
x=1, no.=12
x=2, no.=23
x=3, no.=34
x=4, no.=45
For all these values of 'x', the number is not more than 5 times the sum of digits.
x=5, no.=56
x=6, no=67
x=7, no.=78
x=8, no.=89
For all these numbers, the numbers are greater than 5 times the sum of digits.
So, sum of all possible numbers = 56+67+78+89 = 290