A 2 digit number is 3 times the sum of its digits. What is he number?

Question

I have no idea what to do. I dont even know what operations to use

Answer 1

A two digit number may be written as 10(tens digit) + (ones digit).  For example, 38 = 10(3) + 8.

 

Let x = tens digit and y = ones digit

 

So, 10x+y = 3(x+y)

 

Therefore, 7x = 2y

 

The choices for y are 0, 1, 2, ... ,9.  Since x must be an integer, the only value of y that works is 7.  

 

So, y = 7 and x = 2.  In other words, the number is 27.  

 

 

Answer 2

First, a 2 digit number is 10-99.

 

27.

2 + 7 = 9;

9 * 3 = 27;