The shelf should sell for $235.20.
Marking the price up by 60% means taking 160% of the cost:
160% = 160/100 = 1.6; 1.6(147) = 235.20
B is the answer but i might be wrong .
I think that this is right, but I assumed that the ceiling has the same dimensions as the wall you would need 4 gallons for 2 coats.
Work:
20x8= 160 (square feet for 1 wall)
160x5=800 (i assumed there are 4 walls and 1 ceiling)
800x2=1600 (you need 2 coats)
1600/400=4 (each gallon includes 400 square feet)
