Question

Jazmine is on a trịp to San Antonio, a distance of 330 km. She only has 3.5 hours to get to a job interview there. She gets stuck in traffic for the first 1.5 hours out of Houston and averages a speed of 60 km/hr. In order to not be late, what speed does she need to travel for the rest of the trip? (Organize your information carefully - total, first part, second part)

Answer 1

Jazmine must travel for the rest of the trip at 120km/hr.

Explanation:

To find the speed for the latter half of the trip necessary to arrive on time, we can divide the remaining distance by the remaining time.

The remaining distance, in km, is found by subtracting the distance already covered, which is the product of the speed during the first part of the trip and the elapsed time during this part, from the total distance:

`330-1.5*60=330-90=240`

The remaining time, in hr, is found by subtracting the elapsed time during the first part from the total time limit:

`3.5-1.5=2`

Therefore, the necessary speed in km/hr is:

`\frac{240}2=120`