Quantitative Aptitude - Arithmetic Ability Questions

X and Y together can do a piece of work in 30 days. Y and Z together can do the work in 20 days. X starts the work and works for 15 days then Y takes that work and works for 27 days. Finally Z finishes the remaining work in 9 days. In how many days Y alone can complete the entire work?

A and B can together do a piece of work in 10 days. If A works with twice of his efficiency and B works with an efficiency 1/3rd less than his efficiency, then the work gets completed in 6 days. In how many days can A and B do the work alone respectively?

Find the circumference (in cm) of a circle of radius 7 cm.

Two cars start from a house at an interval of 10 min and travel at a speed of 20 kmph. With how much speed should a woman coming from the opposite direction towards the house travel, to meet the cars at an interval of 8 min?

A takes 24 day in completing a work alone. Time taken by A in completing 1/3rd of the work is equal to the time taken by B in completing half of the work. How many days will be taken in completing the work if both A & B start working together?

48 people could complete a task in 17 days. After 6 days, 4 of the workers left. How many days from then will it take to complete the task?

5% of 400000?

The ratio of speed of three racers is 3 : 4 : 6. What is the ratio of time taken by the three racers to cover the same distance?