Working alone, Jack can do a puzzle in 5 hours. With his brother's help, the two can do the same puzzle in 2 hours. How long would it take Jack's brother to do the puzzle alone?

Omar is going on a road trip! the car rental company offers him two types of cars. each car has a fixed price, but he also needs to consider the cost of fuel. the first car costs $90 to rent, and because of its fuel consumption rate, there's an additional cost of s0.50 per kilometer driven.