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

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?

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.

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 

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?

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:

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? 

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