91Ó°ÊÓ

Solve the equation \(2(\mathrm{x}+3)=(3 \mathrm{x}+5)-(\mathrm{x}-5)\).

Solve the equation \(2[(2 / 3) \mathrm{y}+5]+2(\mathrm{y}+5)=130\)

Two cars are traveling 40 and 50 miles per hour, respectively. If the second car starts out 5 miles behind the first car, how long will it take the second car to overtake the first car?

A tank can be filled in 9 hours by one pipe, in 12 hours by a second pipe, and can be drained when full, by a third pipe, in 15 hours. How long would it take to fill the tank if it is empty, and if all pipes are in operation?