Help please. Thanks!

Jose can do a piece of work in 20 days and his friend can do the same work in 25 days. How long will it take them to finish the work if they will work together?

If the larger of the two numbers which is 36 is divided by the smaller, the quotient is 3 and remainder is 3. What is the smaller number?

The sum of two numbers is 52. If the ratio is 3/10, what are the numbers?

That's all. Thanks!