yeah I have a few problems that i can't solve. help..

Jim can fill a pool carrying buckets of water in 30 minutes. Sue can do the same job in 45 minutes. Tony can do the same job in 1 ½ hours. How quickly can all three fill the pool together?

What simple interest rate will Susan need to secure to make $2,500 in interest on a $10,000 principal over 5 years?

Two angles of a triangle measure 15° and 85 °. What is the measure for the third angle?

thanks