Jason can paint a room in 6 hours. Lorissa can paint a room in only 3 hours. Which of the following can be used to determine the amount of time it would take for Jason and Lorissa to paint a room together?
a-1 over 6 plus 1 over 3 equals 1 over x
b-1 over x plus 1 over 3 equals 1 over 6
c-1 over 6 plus 1 over x equals 1 over 3
d-1 over 3 plus 1 over 6 equals x over 9