In a typing shop, Lalit can complete typing of a book in 9 days, while Amit can finish the same work in 8 days. How many days will they take together to complete the work?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 4.23 days.
Let the total work to be done LCM(9 and 8) be 72 units.
Efficiency of Lalit = 72/9 = 8 units/day
Efficiency of Amit = 72/8 = 9 units/day
Time taken by Lalit and Amit together to complete the work = 72/(8 + 9)
⇒ 72/17 = 4.23 days