Multiple choice

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

  1. 30 days

  2. 30 hours

  3. 5/4 days

  4. 15 hours

  5. 15 days
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

a + b = 5 unit/hour b + c = -4c + a = 32(abc) = 4abc = 2 units in hours means 30 hours to complete = 30/24 days This is correct.

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