Question

Five engineers A, B, C, D and E can complete a process in 8 hrs, assuming that every engineer
works with same efficiency. They started working at 10:00 am, If after 4:00 pm, one engineer
is removed from the group every hour, what is the time when they will finish the work, at night​

Answer 1

Answer:

5 workers can complete the work in 8 hours so in 1 hour, they can complete 1/8 of the work.

If 5 workers can complete 1/8 of the work in 1 hour, then 1 worker can complete 1/40 of the work in the same time.

Efficiency of 5 workers (E5) = 1/8 per hour

Efficiency of 1 worker (E1) = 1/40 per hour

With this information, we can solve the question.

Hour 1–6 (10 AM to 4 PM): Work done = E5 x Time = 1/8 x 6 = 6/8

Work remaining = 2/8

Hour 7 (4PM to 5 PM): Work done = (E5 - E1) x Time = (1/8 - 1/40) x 1 = 1/10

Work remaining = 2/8 - 1/10 = 10/40 - 4/40 = 6/40

Hour 8 (5 PM to 6 PM): Work done = (E4 - EI) x Time = (1/10 - 1/40) x 1 = (4/40 - 1/40) x 1 = 3/40

Work remaining = 6/40 - 3/40 = 3/40

Hour 9 (6 PM to 7 PM): Work done = (E3 - EI) x Time = (3/40 - 1/40) x 1 = 2/40

Work remaining = 3/40 - 2/40 = 1/40

Hour 10 (7 PM to 8 PM): Work done = (E2 - EI) x Time = (2/40 - 1/40) x 1 = 1/40

Work remaining = 1/40 - 1/40 = 0

Therefore, the work will be completed by 8 PM.

Answer 2

Step-by-step explanation:

Five engineers A, B, C, D and E can complete a process in 8 hrs, assuming that every engineer

works with same efficiency. They started working at 10 : 00 am. If after 4 : 00 pm, one engineer

is removed from the group every hour, what is the time when they will finish the work, at nig