Question

one positive number is 12 times another positive number. The difference between the two numbers is 143

Answer 1

Let x is one positive number
One positive number is 12 times another positive number 12x
12x - x = 143
11x = 143
x = 143/11
x = 13

12x = 12(13) = 156

answer: 2 numbers are 13 and 156

double check:

difference between the two numbers is 143
156 - 13 = 143 

Answer 2

Let x be the unknown number and let's set up an equation.
12x - x = 143
Now solve for x:
11x = 143
x = 13
The positive number is 13.