A man borrowed Rs. 500 at simple interest at 3% per annum and Rs. 600 .at '4Y2% per annum on a condition that the total sum will be paid back when total interest amounts to Rs. 126. Find the number of years after which the sum has to be paid back?

1)  2

2)  3

3)  4

4)  5

A and B can separately do a piece of  work in 20 and 15 days respectively. They worked together for 6 days, after which B was replaced by C. If the work was finished in next 4 days, then the number 'of days in which C alone could do the work will be :

1) 60

2) 50

3) 35

4) 40