pump B alone fills a tank in 9 hours. pump C takes 15 hours to fill the same tank alone. If pump A, B and C are used, the tank fills in 5 hours. How long does it take pump A to fill a tank alone?

He concluded that a heavier object dropped from the same height as a lighter object will land

As voters exit the polls, you ask a representative random sample of voters if they voted for a proposition. if the true percentage of voters who vote for the proposition is 63%, what is the probability that, in your sample, exactly 5 do not voted for the proposition before 2 voted for the proposition? the probability is

The area of a circle is equal to 1 dm². find the radius of the circle.