Question

The sum of three numbers is 113 . The second number is 3 times the third. The first number is 7 less than the third . What are the numbers?

Answer 1

Number 1 = 17
number 2 = 72
number 3 = 24


work:

the three numbers are symbolized as x, y, and z

x + y + z = 113

number 2 (y) is 3 times the third number (z) so 

y = 3z

so x + 3z + z = 113

the first number (x) is 7 less than than the third number (z) so

x = z - 7

so z -7 + 3z + z = 113

5z - 7 = 113
5z = 120

z = 24

x = 17
y = 72

Hope this helped :)