Quantitative Aptitude - Arithmetic Ability Questions

Pipe A can fill an empty cistern in 4 hours while along with Pipe B it can fill it up in 3 hours. Only Pipe A is turned on for an hour after which Pipe B is also turned on. How much total time will it take to fill up the cistern?

P and Q undertook to do a work for Rs 7200. P alone could do it in 20 days and Q alone in 12 days. With the assistance of R they finished the work in 5days. What is the share (in Rs) of R?

If there are four lines in a plane, then what cannot be the number of points of intersection of these lines?

The average of 17 results is 60. If the average of first 9 results is 57 and that of the last 9 results is 65, then what will be the value of 9th result?

If tan2A + cot2A + 2 = x, then the value of x is

Mr. Devesh borrowed Rs.4,500 at 4% per annum compound interest. The compound interest compounded annually for 2years is

If a = 3+23-2, b = 3-23+2 then a2+b2-ab ?

The variance of a set of data is 121. Then the standard deviation of the data is