after the 68-second period how much time in seconds will it take for the scientist to travel back to sea level at 4.3 feet per second?

Icould really use some with this question.

Math question.. plz me .. best answer all

Which of the following are independent events? a) knowing that it is going to rain tomorrow, and bringing an umbrella to schoolb) knowing that you have to get up early tomorrow, and going to bed before 9 p.mc) knowing that it is going to rain tomorrow, and going to bed before 9 p.md) knowing that you have a test in school tomorrow, and studying thw night before