Speed Distance!!

Q. After every 45 min trip, a car will take a 15min break. In highway, the car's rate is 60m/h, and in country road, the rate is 40m/h. In a 4 hour trip, the car can travel how many more miles in highway than in country road?

Solution :

We know that for every 45 min ,the car will take 15 min break.
So,for 4 hours travel the car would take 15min *4 = 1 hour break.

Hence,Total time for which the car would travel is 3 hours only (and not 4 hours as 1 hour goes for break).

Now , we know the rate at which the car can travel in both kind of roads .Lets calculate the distance travelled :

Highway road : 3hr * 60 = 180 miles.
Country road : 3 hr * 40 = 120 miles.

We are asked the difference = 180 -120 = 60 miles.