Answer:
48 days
Step-by-step explanation:
In terms of rooms per day, the rates add up as ...
(1/J +1/B) +(1/W +1/N) -(1/J +1/W) = 1/12 +1/16 -1/8
1/B +1/N = (4+3-6)/48 = 1/48
Bob and Nick working together can paint 1/48 of the room each day. It will take 48 days for Bob and Nick to paint the room.
I believe graph D shows proportional relationship
