some problems on time and work

Time and Work

1. A man working alone can do a piece of work in 20 days while a woman working alone can do the same piece of work in 30 days. In how many days will the work be completed if the man and woman work together?

2. 'A' can do a piece of work in 9 days. If 'B' is 50% more efficient than A, find the number of days required by B to complete the piece of work?

3.A and B can respectively do a piece of work in 20/3 days and 5 days. They work together for 2 days and then A leaves . How many more days will it take for B to complete the work?

4. If 3 men and 5 women can do a piece of work in 8 days, and 2 men and 7 children can do the same piece of work in 12 days, then find how many children's work in a day is equal to the work of 10 women in a day?

5.Two pipes A and B can separately fill a tank in 12 hours and 16 hours respectively. A third pipe C can empty the tank in 8 hours. If all the three pipes are left open, how much time will it take for the tank to be filled?

6. A garrison has enough food for 52 days. After 20 days, 400 more soldiers arrived at the garrison. Now for the increased number of soldiers the food will last for only 24 days. How many soldiers were there originally in the garrison?

7. 40 men can dig a ditch 20m X 10m X 1m in 50 days. How many men will be required to dig another ditch 25m X 8m X 1m in 40 days ?

answers

short notes on time and work



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