Last week, the thickness of the ice on a lake increased by (25)/(t+3) centimeters per day (where t is the number of days since the ice first formed). By how may centimeters did the thickness of the ice increase between t=0 and t=4? pls help :)

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