Multiple choice

Kamlesh worked $27$ days and completed $75$ percent of particular work. Then he took help of Lucifer and they together completed the remaining work in $5$ days . How long will Lucifer take to complete the same work, if he is working alone?

  1. $40$
  2. $45$
  3. $50$
  4. $52$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Kamlesh does 75% in 27 days, so his rate is 75/27 = 25/9 percent per day. Together they do 25% in 5 days, so their combined rate is 25/5 = 5 percent per day. Lucifer's rate = 5 - 25/9 = 20/9 percent per day. Time for 100% = 100 / (20/9) = 45 days.

AI explanation

Since 75 percent is 3/4 of the work, Kamlesh completes 3/4 of the work in 27 days. Using the unitary method, Kamlesh alone would complete the entire work in 27 divided by 3/4 days, which equals 36 days. The remaining 1/4 of the work is done by Kamlesh and Lucifer together in 5 days, meaning their combined daily rate is 1/20. Subtracting Kamlesh's daily rate of 1/36 from 1/20 gives Lucifer's daily rate of 1/45, meaning Lucifer alone takes 45 days.

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