You have a total of 42 math and science problems for homework. You have 10 more math problems than s

You have a total of 42 math and science problems for homework. You have 10 more math problems than science problems. How many problems do you have in each subject?

Let m be the math problems and s be the science problems. We have two equations:

(1) m + s = 42
(2) m = s + 10

Substitute (2) into (1)
(s + 10) + s = 42

Combine like terms
2s + 10 = 42

Subtract 10 from each side
2s = 32

Divide each side by 2
s = 16

So that means m = 16 + 10 --> m = 26
(m, s) = (26, 16)