A sample of 50 litres of glycerine is found to be adulterated to the extent of 20 % . How much pure glycerine should be added to it so as to bring down the percentage of impurity to 5 %? 

By what number, is the number of accidents that occurred in April is greater than the average number of Accidents that occurred during the 6 months period?

Vivek and Raja had some books whose ratio was 7: 9 and similarly the ratio of books of Abhishek and Raja was 7: 15, then tell us what was the ratio of books of Vivek and Abhishek?

 A principal of Rs. 6120 becomes Rs. 8330 in 2 years when compounded annually at some rate of interest. How much will be the amount if the same principal was compounded half-yearly?

A DVD player was purchased for Rs 4860. At what price should it be sold so that 25% profit is earned?

Two numbers are less than the third number by 50% and 54% respectively. By how much per cent is the second number less than the first number? 

A vessel contains 20 litres of acid. 4 is taken out of the vessel and replaced by the same quantity of water. Next 4 litres of the mixture are withdrawn, and again the vessel is filled with the same quantity of water. Then find the ratio of acid left in the vessel with the quantity of acid initially in the vessel is: