Question

Suppose a car can travel at an average speed of 60km/h from city a to b. If a car travels at an average speed of 72km/h, it would reach city b 15 minutes earlier. Calculate the distance between city a and b.

Answer 1

The distance between city A and city B can be calculated using the average speed formula and the information provided about the time difference. By setting up an equation and solving for 'd', the distance is found to be 90 kilometers.

Step-by-step explanation:

To calculate the distance between city A and city B, we can use the formula for average speed which is Vavg = distance/time. Let the distance be 'd' km. If the car travels at 60 km/h, the time taken to travel this distance would be 'd/60' hours. Traveling at 72 km/h, the time taken would be 'd/72' hours. Since the car reaches 15 minutes (or 0.25 hours) earlier at the faster speed, we can set up the equation:

d/60 - d/72 = 0.25.
Multiplying through by 360 (the least common multiple of 60 and 72) to clear the denominators gives:
6d - 5d = 90,
d = 90 km.
Therefore, the distance between cities A and B is 90 kilometers.