How many litres of water should be added to a 30 litre mixture of milk and water containing milk and water in the respective ratio of 7 : 3 such that the resultant mixture has 40% water in it?

The simple interest on certain sum of money for 15 months at the rate of 7.5% per annum exceeds the simple interest on the same sum at 12.5% per annum for 8 months by Rs. 3250. Find the sum

4 men and 3 women can finish a job in 6 days, and 5 men and 7 women can do the same job in 4 days. How long will 1 man and 1 woman take to do the same work ?

A and B started a business with initial investments in the respective ratio of 5 : 7. If after one year their profits were in the respective ratio of 1 : 2 and the period for A's investment was 7 months, B invested the money for

An army lost 10% of its men in war, 10% of the remaining due to diseases and 10% of the rest were disabled. Thus, the strength was reduced to 729000 active men. Find the original strength of the army.

The speeds of John and Max are 30 km/h and 40 km/h respectively. Initially Max is at the place L and John is at the place M. The distance between L and M is 650 km. John started his journey 3 hours earlier than Max to meet each other. If they meet each other at a place P somewhere between L and M, then the distance between P and M is :

The average weight of boys in a class is 30 kg and the average weight of girls in the same class is 20 kg. If the average weight of the whole class is 23.25 kg, what could be the possible strength of boys and girls respectively in the same class?

A profit of 8% is made by selling a shirt after offering a discount of 12% on the marked price. If the marked price of the shirt is Rs.1080, find its cost price.