The ratio of milk and water in 42 litres of milk and water is 4 : 3. If x litres less of both quantities liquids be mixed up then their ratio becomes 7 : 5. Find the value of x.

By selling 90 chocolates for Rs. 160, a chocolate trader loses 20%. How many chocolates should he sell for Rs. 96 to make a profit of 20%?

At the rate of 8 % simple annual interest, if an amount becomes Rs. 819 in 3 years and 3 months, then what was the original amount?

If the difference of the compound interest and the simple interest on a sum of money for 3 years is Rs. 186. Find the sum of money, if the rate of interest in both cases be 10 % 

Comprehension: Read the following chart and answer the following questions.

What is the difference between the day that had maximum deaths to the day that had minimum deaths? 

A train travels the distance between station P and Q at a speed of 126 km/h, while in the opposite direction it comes back at 90 km/h. Another train travels the same distance at the average speed of the first train. The time taken by the second train to travel 525 km is:

Find the value of. 67²–33².

Find value of $$ {^3\sqrt{\sqrt{0.000729}}}+^3{\sqrt{0.008}}$$