If Sally walked 1⁄2 kilometer in 1⁄4 hour, how fast, in kilometers per hour, was she walking?

Answer 1

Hi Stefany!

To solve this problem, you should expand the given time of 1/4 hour to an hour. Since we know 1/4 hour (15 minutes) is a fourth of an hour we can do:

1. 1/4 hour x 4 = 1 hour

If you multiply one part of the equation by 4, you must do that with the other part of the equation as well:

1. 1/2 kilometer x 4 = 4/2 kilometers (simplified to 2 kilometers)

After expanding the problem, you are left with the information that Sally walked 4/2 kilometers in 1 hour, which you could also write as 2 kilometers in 1 hour. This means if Sally walked 1/2 kilometer in 1/4 hour, she was walking at a speed of 2 kilometers per 1 hour.

Answer 2

Hi Fabiana,

The best way to do this type of problem is to keep track of your units....

To find km/hour sub the values given in the problem, or (1/2 km)/(1/4 hr) = ? km/hr