Q.66- Average cost of 5 apples and 4 mangoes is Rs. 36. The average cost of 7 apples and 8 mangoes is Rs. 48. Find the total cost of 24 apples and 24 mangoes.
Q.67- The average weight of three boys A, B and C is $$\begin{array}{c}\frac{163}{3}\end{array}$$ kg, while the average weight of three boys B, D and E is 53 kg. What is the average weight of A, B, C, D and E?
Q.68- Average of ten positive numbers is x. If each number is increased by 10%, then x :
Q.69- The average price of 10 books is Rs.12 while the average price of 8 of these books is Rs. 11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what is the price of each of these two books?
Q.70- 3 years ago the average of a family of 5 members was 17 years. A baby having been born, the average age of the family is the same today. The present age of the baby is: