Rakesh, Mahesh and Puneesh together can make a chair in 20 minutes. Rakesh and Mahesh together can make it In 25 minutes. How much time will Puneesh alone take to make that chair?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 100 minutes.
According to the question:
Time taken by Rakesh , Mahesh , Puneesh to make chair = 20 min
Time taken by Rakesh , Mahesh to make a chair = 25min
Let total work = Least common multiple of 20 and 25 = 100units
Efficiency of Rakesh , Mahesh and Puneesh together = 100 / 20 = 5 units/ min.
Efficiency of Rakesh and Mahesh together = 100 / 25 = 4 units / min.
Efficiency of Puneesh = 5 - 4 = 1 unit/ min
Time taken by Puneesh to make a chair alone = 100 × 1= 100min.