Q:

In his​ motorboat, Bill Ruhberg travels upstream at top speed to his favorite fishing​ spot, a distance of 24 ​mi, in 2 hr.​ Returning, he finds that the trip​ downstream, still at top​ speed, takes only 1.5 hr. Find the rate of​ Bill's boat and the speed of the current. Let x​ = the rate of the boat in still water and y​ = the rate of the current.

Accepted Solution

A:
Answer:Rate of​ Bill's boat = 14 miles per hourSpeed of the current = 2 miles per hourStep-by-step explanation:Let x​ = the rate of the boat in still water and y​ = the rate of the current.Distance traveled = 24 milesTime taken for upstream motion = 2 hourTime taken for downstream motion = 1.5 hourVelocity of upstream motion = x - yVelocity of downstream motion = x + yWe have            Displacement = Time x VelocityUpstream motion             24 = 2(x-y)              x - y = 12 ----------------------------eqn 1Downstream motion             24 = 1.5(x+y)              x + y = 16 ----------------------------eqn 2eqn 1 + eqn 2              2 x = 28                 x = 14 miles per hourSubstituting in eqn 2                  14 + y = 16                       y = 2 miles per hourRate of​ Bill's boat = 14 miles per hourSpeed of the current = 2 miles per hour