RS Aggarwal Class 8 Math Thirteenth Chapter Time and Work Exercise 13A Solution
EXERCISE 13A
(1) Rajan can do piece of work in 24 days while Amit can do it in 30 days. In how many days can they complete it, if they work together?
(2) Ravi can do a piece of work in 15 hours while Raman can do it in 12 hours. How long will both take to do it, working together?
(3) A and B, working together can finish a piece of work in 6 days, while A alone can do it in 9 days. How much time will B alone take to finish it?
(4) Two motor mechanics, Raju and Siraj, working together can overhaul a scooter in 6 hours. Raju alone can do the job in 15 hours. In how many hours can Siraj alone do it?
(5) A, B and C can do a piece of work in 10 days, 12 days and 15 days respectively. How long will they take to finish it if they work together?
(6) A can do a piece of work in 24 hours while B alone can do it in 16 hours. If A, B and C working together can finish it in 8 hours, in how many hours can C alone finish the work?
(7) A, B and C working together can finish a piece of work in 8 hours. A alone can do it in 20 hours and B alone can do it in 24 hours. In how many hours will C alone do the same work?
(8) A and B can finish a piece of work in 16 days and 12 days respectively. A started the work and worked at it for 2 days. He was then joined by B. Find the total time taken to finish the work.
(9) A can do a piece of work in 14 days and B can do it in 21 days. They began together and worked at it for 6 days. Then, A fell ill and B had to complete the remaining work alone. In how many days was the work completed?
(10) A can do 2/3 of a certain work in 16 days and B can do ¼ of the same work in 3 days. In how many days can both finish the work, working together?
(11) A, B and C can do a piece of work in 15, 12 and 20 days respectively. They started the work together, but C left after 2 days. In how many days will the remaining work be completed by A and B?
(12) A and B can do a piece of work in 18 days; B and C can do it in 24 days while C and A can finish it in 36 days. In how many days can A, B, C finish it, if they all work together?
(13) A and B can do a piece of work in 12 days, B and C in 15 days, and C and A in 20 days. How much time will A alone take to finish the job?
(14) Pipes A and B can fill an empty tank, in 10 hours and 15 hours respectively. If both are opened together in the empty tank, how much time will they take to fill it completely?
(15) Pipe A can fill an empty tank in 5 hours while pipe B can empty the full tank in 6 hours. If both are opened at the same time in the empty tank, how much time will they take to fill it up completely?
(16) Three taps A, B and C can fill an overhead tank in 6 hours, 8 hours and 12 hours respectively. How long would the three taps take to fill the empty tank. If all of them are opened together?
(17) A cistern has two inlets A and B which can fill it in 12 minutes and 15 minutes respectively. An outlet C can empty the full cistern in 10 minutes. If all the three pipes are opened together in the empty tank, how much time will they take to fill the tank completely?
(18) A pipe can fill a cistern in 9 hours. Due to leak in its bottom, the cistern fills up in 10 hours. If the cistern is full, in how much time will be emptied by the leak?
(19) Pipe A can fill in 6 hours and B can fill it in 8 hours. Both the pipes are opened and after two hours, pipe A is closed. How much time will B take to fill the remaining part of the tank?
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