Ethan drove one half of a kilometer and 20 seconds. which of the following shows his speed in kilometers per minute.

The answer is B: 1 1/2 kilometers per minute
In order to solve this equation you have to make the numbers into a ratio: 1/2:20. Then you have to multiply 20 seconds by 3 to get 60 seconds which is equal a minute. Whatever you do to one side of the ratio you have to do to the other, so you have to multiply 1/2 by 3 as well. In the end you will get the ratio 1 1/2 kilometers: 60 seconds (1 minute).