Question 530315
I can see only one additional step that you might have included!
Let P = The number of problems Paul worked on.
Let J = The number of problems Jean worked on.
1) P = J+7 "Paul worked 7 more problems than Jean."
2) P+J = 55 "Together they worked 55 problems."
Substitute the P from equation 1) for the P in equation 2).
2a) (J+7)+J = 55 Simplify.
2b) 2J+7 = 55 Subtract 7 from both sides.
2c) 2J = 48 Divide by 2.
2d) J = 24 Substitute into equation 1)
1a) P = 24+7
1b) P = 31
Paul worked 31 problems and Jean worked 24 problems.