What will be the difference between the compound interest and simple interest at the rate of 5% per annum on an amount of Rs 4000 at the end of 2 year?

If three numbers are in the ratio 3:5:6 and their LCM Is 2160, then find their HCF.

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.

Two varieties of rice, A and B, costing Rs.210 and Rs.280 per kg respectively are mixed in the ratio of 3:4. The mixed variety is sold at Rs. 260 per kg. What is the profit percentage?

À train consists of 12 bogies, each bogie is 15 m long. The train crosses a telegraph post in 18 s. Due to some problem, two bogies were detached. The train now cresses the telegraph post in 

In a town, the population was 8000. In one year, male population increased by 10% and female population increased by 8% but the total population increased by 9% . The number of males in the town was:

What will come in place of question mark(?) in the following number series?
11, 57, 149, 333, 701 (?)

Pipe A can fill a tank in 4 hours and pipe B can fill it in 6 hours. If they are opened on alternate hours and if pipe A is opened first then in how many hours, the tank shall be full?