The marked price of an article is Rs.800. A retailer buys it for Rs.540 after getting two successive discounts. The first discount is 25 %. What is the second discount?

Find the standard deviation of the following data (rounded off to two decimal places). 5, 3, 4, 7 

Find two such numbers whose middle proportional is 18 and third proportional is 144.

The length of diagonal of a square is $${15\sqrt { 2}}$$cm. Its area is

A furniture salesman increased the value of furniture by 20 percent due to the lure of more income, which led to a decrease of 30 percent in his sales, then tell him what percentage was reduced in his income?

A person goes from P to Q in 8 hours. He starts from P at 8 a.m. Another person goes from Q to P in 12 hours. He starts from Q at 9 a.m. At what time will they meet?

The average of the largest and smallest 3 digit numbers formed by 0, 2 and 4 would be 

The adjacent angles on a straight line are in the ratio 5 ∶ 4, then the smaller angle is –