Word Problems. Kinda hard?

Question

Chris can row a boat a distance of 20 miles in 2.5 hours when he is rowing with the current. It takes him 3 hours to row the same distance when he is rowing against the current. What is the rate of the current?

Answer 1

This equation is a two-variable system. From the problem we understand the equations are in the form of distance=rate*time. Let b=boat speed, and c=current speed.

(b+c)2.5=20

(b-c)3.0=20

Now isolate the variables on the left side of the equation

b+c=8

b-c=(20/3)

Now, you can solve the system by means of elimination. Find the difference of the two equations together so as to eliminate the variable b.

2c=(4/3)

c=(2/3)

Therefore, the speed of the current is 2/3 miles/hour or roughly .66 mph