If the population of a town is 64000 and its annual increase is 10%, then its population at the end of 3 yeas will be :

A contract is to be completed in 50 days and 105 men were set to work, each working 8 hour a day. After 25 days, 2/5th of the work is finished. How many additional men be employed, so that the work may be completed on time, each man now working 9 hour a day?

The simple interest of 7 years of money is Rs. 1750. If the rate of interest was 2% more per annum, how much interest would have been higher?

If a + b = -2 and a - b = 12, find b. 

The ratio of the area of a square to that of the square drawn on its diagonal is :

A bus can cover a distance of 420 km in 7 hours. How much will the speed have to be increased to cover this distance in 6 hours?

The difference between CI and SI on a sum of money for 3 years at 5% per annum is Rs.61. Find the sum.

Arun purchased 30 kg. of rice at the rate of Rs. 17.50 per kg. and another Rs. 30 kg. at a certain rate. He mixed the two and sold the entire quantity at the rate Rs. 18.60 per kg. and made 20% overall profit. At what price per kg. did he pruchase the lot of another 30 kg. rice?