a group of four 70-year old men, the probability distribution for the number who live through the

Jerri has 210 stamps in her collection. She wants to arrange her stamps in a rectangular array so there are the same number of stamps in each row without any left over. What are all the different ways she can arrange her stamps, not worrying about order?

A tank can be filled by 2 water keys together in 3 hours with 3 quarters. The main key would be able to fill it by itself in 4 hours less than the other one. In how many hours can each key fill the tank separately?

Travis's carpet has an area of 180 square feet. He hires the CarpetPro carpet cleaning service, which is able to clean 9 square feet of his carpet every minute. Therefore, in the first minute, CarpetPro is able to clean 9 square feet of Travis's carpet (leaving 171 square feet remaining to be cleaned). In the second minute, the cleaner is again able to clean 9 square feet of carpet (leaving 162 square feet to be cleaned), etc. Which of the following functions expresses the number of square feet that still remain to be cleaned after t minutes from the time that the carpet cleaner began cleaning this carpet.   A(t)=180−0.9t A(t)=180(0.1)t A(t)=180(0.9t) A(t)=180−9t A(t)=180−0.1t