PLEASE HELP! One inlet pipe can fill an empty pool in 8 hours, and a drain can empty the pool in 20 hours. How long will it take the pipe to fill the pool if the drain is left open?
hours:

An eight-sided die, which may or may not be a fair die, has four colors on it; you have been tossing the die for an hour and have recorded the color rolled for each toss. what is the probability you will roll a brown on your next toss of the die? express your answer as a simplified fraction or a decimal rounded to four decimal places.

How do i put 3(x+7) in distributive property

If 1.4% of the mass of a human body is calcium, how many kilograms of calcium are there in a 165-pound man? 1.0 kg ca 5.1 kg ca 1.0 x 102 kg ca 5.1 x 102 kg ca