**Question:**

**71
Each lap of a swimming pool is 50 m. Joey swims 30 laps.How many kilometres does Joey swim altogether?12The thickness of a dictionary is 4.3 cm. What is the total height of astack of 50 such dictionaries? Give your answer in metres.13The total mass of 10 identical tins of milk powder is 16 kg.What is the mass of 4 such tins?14The cost of 100 g of grapes is $0.55 at a supermarket.What is the cost of 3 kg of grapes?**