A can do a piece of work alone in 30 days. B is 25% less efficient than A, while C is $$33{1\over 3}$$ % more efficient than B. In how many days can A, B and C, working together, complete the work?

A person has some coins of ₹10, ₹5, and ₹2 denominations. The ratio of the products of the numbers of ₹10 and ₹5 coins, the numbers of ₹5 and ₹2 coins, and the numbers of ₹2 and ₹10 coins is 3: 4: 2 respectively. What could be the minimum amount of money this person has? 

The price of diesel increases by 5% every year. If the current price of diesel is ₹80 per litre, then what will be the price of diesel per litre after 2 years?

What number must be subtracted from each of the numbers 55, 23, 43 and 19, so that the new values are in proportion? 

The speed of a boat in still water is 10 km/h. The speed of the stream is 2 km/h. What is the total distance that the boat will travel if it is rowed for 4 hours upstream and 3 hours downstream?

The average weight of A, B, and C is 52 kg. If the average weight of B and C is 44 kg and that of C and A is 46 kg, then what will be the weight of C?

The LCM of two positive integers is twice the larger number and the HCF of the two numbers is 3. The smaller number is:

P₁ alone can do $${2\over 3}$$  of the work in 8 days. P₂ alone can do $${7\over 12}$$  of the work in 14 days. P₃ alone can do $${8\over 15}$$   of the work in 16 days. In how many days can they complete the work, if all three work together?