If the two taxis depart at the same time, how much time will pass before they are 17 kilometers apart?

Question

Some friends are leaving a party in Campbell to go home. One group takes a taxi uptown, traveling north at 50 kilometers per hour. The rest of the friends share another taxi, traveling south at 72 kilometers per hour. Answer in minutes

Answer 1

Mae,

This is a distance = rate x time problem.  Let x be the number of hours they have to travel.  The distance they travel going north is 50 x, going south is 72 x .  The distance they are apart is 50 x + 72 x ,  and we want to know what is x when they are 17 km apart.

 

50x + 72 x = 17

122 x = 17

x = 17/122 hours X 60 min./hr. ∼8.4 sec.

 Hope you followed all the steps.

Mary