Question

A hot air balloon leaves the ground and ascends at a rate of 5 feet per minute for 4 minutes.

Answer 1

When the balloon is on the ground, it is at point 0. It starts to go up at 5 f/m for a time of 4 minutes. So we will multiply 5 by 4 to get 20. At this point, the balloon is 20 feet off the ground. However, we now know that the balloon descends at 2 f/m at a time of 7 minutes. So we must multiply 2 by 7 to get 14. So we know it was at 20, and then it went down by 14.

20 - 14 = 6 feet

This means that the balloon is now 6 feet above the ground.

I hope I've helped! :)