Q:

# Traveling downstream a certain boat went 16 mph. Traveling upstream it only went 4 mph. What is the speed of the current? How fast would the boat go if there were no current?

Accepted Solution

A:
The speed of current is 6 mph. If there is no current, then boat would go with speed of 10 mphSolution:Formula to remember for this problem:If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then:Speed downstream = (u + v) km/hrSpeed upstream = (u - v) km/hrGiven that Traveling downstream a certain boat went 16 mphlet s = the boat speed in still water let c = the rate of the currents + c = 16  --- eqn 1Also given that Traveling upstream it only went 4 mphs - c = 4  ----- eqn 2Add eqn 1 and eqn 2s + c = 16s - c = 4(+) ----------------2s = 20s = 10Substitute s = 10 in eqn 110 + c = 16c = 6Thus the speed of current is 6 mphHow fast would the boat go if there were no current?We have found out that speed of current is 6 mphIf there is no current means,s - c = 4s - 6 = 4s = 10 mphThus if there is no current, then boat would go with speed of 10 mph