68) The average of 8 numbers is 280. The average of 6 of these numbers is 320. What is the average of the remaining two numbers.

69) A shopkeeper has Rs. 10 in form of 2 paise, 5 paisa and 25 paisa coins are in the ratio 25:5:2. find the number of 2 paisa coins with the shopkeeper?

70) In a mixture of 30 liters, the ratio of juice and sugar syrup is 7:3. How much more sugar syrup must be added to make its ratio 1:2?

71) Find the number whose 62% of 5/8 is 2790?

72) Find the rate at which the money becomes 5 times in 20 years at simple interest