Belinda can throw a ball at a speed of 20 feet/second. If the ball flies for 8 seconds before hitting the ground, and Belinda's border collie can run 5 feet/second, how many seconds will it take the border collie to catch up to the ball?
First find the total distance the ball flies: 20 feet/second * 8 seconds = 
<gadget id="calculator">20*8</gadget>
<output>160</output>
160 feet.
Then divide that distance by the dog's speed to find how long it takes the dog to catch up to the ball: 160 feet / 5 feet/second = 
<gadget id="calculator">160/5</gadget>
<output>32</output>
32 seconds.

<result>32</result>