Quantitative Aptitude - Arithmetic Ability Questions

Sashi can do a piece of work in 20 days. Tanya is 25% more efficient than Sashi. The number of days taken by Tanya to do the same piece of work is:

A and B can together complete a task in 18 hours. After 6 hours A leaves. B takes 36 hours to finish rest of the task. How many hours would A have taken to do the task if he worked alone?

The average of 12 numbers is 35. If four numbers 20, 27, 15 and 29 are removed then what will be the average of remaining numbers?

A wholesaler sells a watch to a retailer at a profit of 33% and the retailer sells it to a customer at a loss of 20%. If the customer pays Rs 2,181.2, what had it cost the wholesaler?

P bought an article for Rs. 1600 and sold it at a profit of 10%. What would have been the increase in the profit percent if it was sold for Rs. 1840?

2 litre of pure alcohol is added to 6 litre, 40% alcohol solution. The percentage of water in the solution is _____ .

A carpenter can build a cupboard in 64 hours. After 16 hours he takes a break. What fraction of the cupboard is yet to be built?