Math question

Question

A train leaves Little Rock and travels north at 55 kilometers per hour. Another train leaves at the same time and travels south at 90 kilometers per hour how long will it take before they are 290 kilometers apart

Answer 1

Because the amount of time, t, is the same for both and they are going in directly opposite directions, we need to add the distances that each train traveled in the time, t, so that they equal 290 km.

The distance that the northbound train travels in time, t, is 55t.

The distance that the southbound train travels in time, t, is 90t.

Therefore,   55t + 90t = 290

                  145t = 290                add like terms

                  145t/145 = 290/145   divide both sides by 145 to isolate t

                       t = 2                     answer is in hours

So, the answer is 2 hrs.

Answer 2

d = rt

d1 = 55t

 

d2 =90t

 

d1+d2 = 290

 

55t+90t = 290

 

145t=290

t = 2

 

It takes 2 hours for the two trains to be 290 km apart.