A boat goes 15 km in an hour in still water, and takes thrice the time to cover the same distance upstream. The speed of the current (in km / hr) is –

A four digit number is formed by writing a two digit number together twice like: 15:15, -3737 etc. A number of this form will be exactly divisible by which of the following numbers 

Mohshin has 5 daughters. The average age of these 5 sisters is 28 years. The youngest one is 16 years old. What was the average age of the 4 daughters before the youngest one was born?

Monu and Kitu entered into a partnership for a year in which Monu invested Rs 120000 and Kitu invested Rs 70000. After 4 months, Monu invested Rs 80000 more whereas after 5 months, Kitu invested Rs 30000 more. When two months were left Sweety also joined investing Rs 400000 as her contribution. If the profit for the year was 12.5% of 1572000, find the share of Monu, Kitu and Sweety.

A man bought three articles, each of which cost Rs 3000. He sold those articles at 10% profit, 5% profit and 15% loss respectively. What is the total profit/loss percentage earned by him?

In 64 liter of pure alcohol, 20 liter of water is mixed and then $$ {1\over 4}{th}$$ of the mixture is taken out. When x liter of water is added again then ratio of water to that of the alcohol becomes 1:2. Find value of x?

The ratio of the marks of Kamlesh in the examination of two subjects English and Mathematics is 7 : 11. If he got 20 marks more in Mathematics than in English, then how many marks did he get in English?

Piyush is running at the speed of 8 km/h and he stops for 5 minutes at the end of every third kilometer. How much time will Piyush take to cover a distance of 56 km?