Word problems : ALGEBRA, help please!

1.) The sum of two numbers is 125. The second number is 5 more than the first. Find the numbers. (somehow related to translating words to mathematical symbols).

2.) Maria can clean the a house in 4hours, Juana in 6 hours and Petra in 8 hours. How long will it take to clean the house if Maria and Juana work 1 hour and then Maria and Petra finish the job?

3.) A carpenter can build a house in 21 days, another can do it in 28 days, and third can do it in 48 days. How long will it take to do the job if they all work together?



I'll answer the first question.. it's 60 and 65 :)