Solve the following Problem: 

The average age of a committee of 8 members is 40 years. A member aged 55 years retired and his place was taken by another number aged 39 years. What will be the average age of the present committee?

M can do a piece of work in 40 days. He works at it for 5 days and then N alone finishes the remaining work in 42 days. The two together could complete the work in how many days?

In a shop, the cost of 4 shirts, 4 pairs of trousers and 2 hats is Tk. 560. The cost of 9 shirts, 9 pairs of trousers and 6 hats is Tk. 1,290. What is the total cost of 1 shirt, 1 pair of trousers and 1 hat?