A rower travels upstream at 6km/h and back to the starting place at 10km/h. The total journey takes 48 minutes. How far upstream did the rower go?

Question

we have to construct an equation for the problem and then solve it

Answer 1

Let x = one way distance

 

Distance = (Rate)(Time)

 

So, Time = Distance/Rate

 

Since the rates are measured in km/hr and time is measured in minutes, we need to convert hours to minutes, or minutes to hours.  I will convert minutes to hours:  

48 min = (48 min)(1 hr/60 min) = 4/5 hr.

 

Time upstream + Time downstream = 4/5

 

Therefore, x/6 + x/10 = 4/5

 

              Multiply both sides by the LCD, 30:  5x + 3x = 24

 

                                                                        8x = 24

 

                                                                          x = 3 km