Question

The sum of three numbers is 125. The second number is 3 times the third. The third number is 10 less than the first. What are the numbers?

Answer 1

form simultaneous equations.
a + b + c = 125
b = 3c
a = c +10
Substitute them back in:
c + 10 + 3c + c = 125
Solve for c:
5c + 10 = 125
5c = 115
c = 23
a = 23 + 10 = 33
b = 3 x 23 = 69
To check:
23 + 33 + 69 = 125, Which is correct