John and Paul spent $45 altogether. John and Henry spent $65 altogether. If Henry spent 3 times as much as Paul, how much did John spend?

Answer 1

Hi! I agree with the posted answer by Mark M. and would add a step just in case it is not obvious how he derived 2p = 20.

One approach is subtracting one equation from the other in order to isolate p.

 j + 3p = 65

–    j + 1p = 45

     =========

           2p = 20

p = 10

Answer 2

j represents what John spent

p represents what Paul spent

3p represents what Henry spent

j + p = 45

j + 3p = 65

2p = 20

p = 10

j = 35