Answer:
a)27-x
b)27+x
Step-by-step explanation:
when a boat travels in the same direction as the current is downstream-->speeds the boat. If the rate of the boat in still water is 27 mph and the rate of the current of a river is x mph, the rate of the boat when the boat is going downstream is 27+x
when a boat travels against the current is upstream-->slow down. If the rate of the boat in still water is 27 mph and the rate of the current of a river is x mph, the rate of the boat when the boat is going upstream is 27-x
108 = ( x)(48-x)
108 = 48x - x^2
48x -x^2 -108 = 0
I'm assuming you're doing solve the square right now, so you should be able to do the rest.