I need help solving this word problem

Question

Update : A man can drive a motorboat 45 miles down the Colorado River in the same amount of time that he can drive 27 miles upstream. FInd the speed of the current if the speed of the boat is 12 mph in still water

Answer 1

Down stream distance = 45 miles

Up stream distance = 27 miles

Speed of the boat in still water = 12 mph

Let x be the speed of the current

Down stream speed = Boat speed + current speed = 12 + x

Up stream speed = Boat speed - current speed = 12 - x

Time upstream = Time downstream

45 (12-x) = 26 (12+x)

540-45x = 312 + 26x

45x + 26x = 540 - 312

71x = 228

x = 3.21

The Speed of the current is 3.21 mph