The average age of 24 boys and their teacher is 15 years. When the teacher's age is excluded, the average age decreases by 1 year. The age of the teacher is: 

If the cost of production of an article is 2/5 of its marked retail price, If it is sold at 10 % discount then what will be profit ? 

What is the quantity of water should be added to a 75 litre mixture of milk and water so that the percentage of milk in the mixture decrease from 75% to 45%?

1200 soldiers in a fort had enough food for 28 days. After 4 days, some soldiers left the fort. Thus, food lasted for 32 more days. How many soldiers left?

Excluding stoppages, the speed of a train is 120 kmph and including stoppage, it is 50 kmph. For how many minutes does the train stop per hour?

Sanjana invested Rs. 15000 in SI at the rate of 2x% per annum for two years and the same amount is invested in CI at the same rate of interest if she received Rs.150 more interest than S.I, then find the rate of interest per annum?

 The least number by which 448 is to be divided to make it a perfect cube is

Find the amount (integral value only) if a sum of ₹6,500 is being borrowed at 10% interest per annum for 2 years if interest is compounded half-yearly.