Question

A remote-controlled boat can travel at 4 feet per second in calm water. the boat traveled 48 feet with the current, and then it traveled 16 feet against the current in the same amount of time. How fast is the current?

Answer 1

Speed of the boat with current = (4+c) ft/s
Speed of the boat against current = (4-c) ft/s

Where, c= speed of the current

Speed = Distance/Time => Time = Distance/Speed

In both cases, time is equal
Therefore,

48/(4+c) = 16/(4-c) => 48(4-c)=16(4+c) => 192-48c = 64+16c => 192-64 = (48+16)c => 128 = 64 c => c= 128/64 = 2 ft/s

The current is travelling at 2ft/s