Multiple choice

Three technicians a, b and c have a work to make a server. a and b can make a server in 12 hours, b and c can destroy that server in 15 hour, and c and a can make the server in 20 hours. In how many days will the server be ready to work if a works alone?

  1. 10 hours

  2. 5/12 days

  3. 5 hours

  4. 5/24 days

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Use unitary method ab = 12 = 5 unit out of lcm of time 60 bc =15 = -4ca = 20 = 32abc = 4abc = 2 So, a = 6b = -1c = -3 So, 10 hour = 5 /12 day This is correct.

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