A, B and C can complete a work in 10, 20 and 30 days respectively. If D can destroy the same work in 15 days. Find the time taken by all of them to complete the whole work.

There were two candidates in an election, total 7500 votes were cast, 20% of these votes were declared invalid, if one candidate got 55% of the valid votes then how many valid votes did the other candidate get?

If the area of a triangle is 616 square cm, then its perimeter will be-

By selling 25 m of cloth a man gains the selling price of 5 m of cloth. Find the gain percent?

The following Charts shows the amount of grain exported (in million kg ) by a country during 2013–18.

What is the maximum per cent more than the minimum export in the given period?

The mean of the first 7 prime numbers is:

A person invests money in three different schemes for 6 years, 10 years and 12 years at 10%, 12% and 15% simple interest respectively. At the completion of each scheme, he gets the same interest. The ratio of his investments is-

Two students appeared for an examination. One student who scored 20 marks more than the other, his score was 60 % of the sum of their marks. What was his score?