Terry has completed 15 homework problems, and Susan has competed 9. Terry is completing 10 problems per hour and Susan is competing 12 problems per hour. After how many hours will terry and susan have completed the same number of problems ??
terry = 15 + 10 t
susan = 9 + 12 t
so
15 + 10 t = 9 + 12 t
2 t = 6
t = 3 hours