A sum of money becomes double in 3 years at compound interest compounded annually at the same rate. In how many years will it become four times of itself? 

After allowing a discount of 12% on the marked price of an article, it is sold for Rs. 880.Find its marked price.

A train 150 m. long is running with a speed of 68 km. /hr. In what time will it pass a man who is running at 8 km. /hr. in the same direction in which the train is going?

A and B can do a piece of work in 28 and 35 days respectively. They began to work together but A leaves after sometime and B completed remaining work in 17 days. After how many days did A leave? 

If 4 litres of water is evaporated on boiling from 12 litres of salt solution containing 7 percentage salt, the percentage of salt in the remaining solution is 

The sum of three numbers is 116. The ratio of second to the third is 9 : 16 and the first to the third is 1 : 4 The second number is 

The LCM of two positive integers is twice the larger number. The difference of the smaller number and the GCD of the two numbers is 4. The smaller number is: 

If the time in clock is 12 : 23. What is the time in the mirror?