New wave mental maths 4

Here are 4 new wave mental math problems for you to solve:

Problem 1 A bookshelf has 5 shelves, and each shelf can hold 8 books. If the bookshelf is currently empty, how many books can be placed on it in total?

Problem 2 A bakery is making a special batch of cookies. They need to package 48 cookies into boxes that hold 6 cookies each. How many boxes will they need?

Problem 3 A car travels from City A to City B at an average speed of 60 km/h. If the distance between the two cities is 240 km, how long will the trip take?

Problem 4 A group of friends want to share some candy equally. If they have 36 pieces of candy and there are 6 friends, how many pieces of candy will each friend get?

Take your time, think carefully, and see if you can solve them mentally!