
Jason U. answered 02/26/19
Computer Science (M.Sc.) and Mathematics (B.Sc.) Tutor of 10+yrs
Let's name the number in question 'n'. The problem statement can then be written as:
n - 16 = 3n -36
Collecting all unknowns on one side and moving everything else to the other:
n - 16 = 3n - 36 | -n
-16 = 3n - n - 36 | + 36
36 - 16 = 3n -n
20 = (3 - 1)n
20 = 2n | ÷2
n = 10
The number is 10.