Question

A two-digit number is three times the sum of its digits. Then the unit place digit of the number is- 

2
7
5
9
​

Answer 1

Step-by-step explanation:

let the 2 digit number be 10x+y

sum of digits =x+y

10x+y=3(x+y)

x+y=10x+y/3

since 10x+y is divisible by 3 then it's units place must have multiple of 3

so answer is 9