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 make that server in 15 hours, and c and a can make the server in 20 hours. In how many days will the server be ready to work if initial 5 hours of work is done by a and after that b and c will complete the work?

  1. 10 days

  2. 5 hours

  3. 5/24 days

  4. 5/12 days

  5. 35/48 days
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

ab = 12 = 5 in 60 lcm of time bc = 15 = 4ca 20 = 32 a b c = 12abc = 6 So, a = 2b = 3c = 1 initial 5 hours of work is done by a, i.e. 10 units is completed. Rest of the work is completed by bc = 4 means 50/4h 5 + 50/4 = 35/2h This answer is correct.

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