Motorway Police Question: Complete the series. 6, 9, 13, 16, 20, 23, _______? Motorway Police Officer Interview QuestionAnswer: 27, 30 Previous QuestionNext QuestionIf a car drives 25 kilometres on two litres of petrol, how many litres will be needed for trip of 150 kilometres?A man buys a shirt for Rs. 70 after getting a discount of 20%. What was the marked price on the shirt?