Directions: The Bar Graph given here shows the population (in crores) of India in various census years. Observe the graph and answer the question based on it.  

Per year increase in population from the year 1931 to 1981 is 

Two sums are in the ratio 4:3. Both the sums are lent at 5% per annum and 10% per annum under compound interest for two years. The difference between the interest at the end of two years is Rs. 1540. What was the sum lent at 10% per annum?

Three pipes A, B and C can fill a cistern in 10 hours, 12 hours and 15 hours respectively. First A was opened. After 2 hour, B was opened and after 4 hours from the start of A, C was also opened. Find the time in which the cistern is just full.

If the cost of pins reduces by Rs . 4 per dozen, 12 more pins can be purchased for Rs. 48. The cost of pins per dozen after reduction is: