A factory plans to produce a batch of parts, 12 people work 6 hours, completed 60% of the plan, according to this calculation, the remaining 20 people do, how many hours?

60% △ 6 △ 12 = 1 / 120
(1-60%) / (1 / 120 × 20) = 2.4 (hours)
A: 2.4 hours
Oh, give me extra points!

If an engineering team wants to complete a project, it will finish three fifths of the project in 12 hours. According to this calculation, the rest of the project will be completed in a few hours

(1-3 / 5) / ((3 / 5) / (12) = 8 (hours), that is, the rest of the project will be completed in 8 hours

For a project, team a can complete 1 / 4 of the project in 5 hours alone, and team B can complete half of the project in 8 hours alone. The work efficiency ratio of team a and team B is ()

Team a can finish 1 / 20 of the project in an hour
Team B can finish 1 / 16 of the project in an hour
So the efficiency ratio of team a and team B is 16:20, that is 4:5

For a project, it takes 10 days for Party A to do it alone, and 15 days for Party B to do it alone. If two people cooperate, their work efficiency will be reduced. Party A can only complete the original 45, and Party B can only complete the original 910. They need 8 days to complete the project, and the number of days for two people to cooperate is as small as possible. How many days do they have to cooperate?

The number of days of cooperation is x, (110 × 45 + 115 × 910) x (110 × 45 + 115 × 910) x (110 × 45 + 115 × 910) x + 110 × (8-x) (8-x) and the number of days of cooperation is x, (110 × 45 + 115 × 910) x ((110 × 45 + 115 × 910) x (110 × 45 + 115 × 910) x (110 × 910) x + 110 (8-x) x (8-x) as (8-x)) is the first & nbsp & nbsp & nbsp; & & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & & nbsp; & nbsp & nbsp; & & nbsp; & & nbsp; & nbsp; & nbsp; & nbsp & nbsp; & & nbsp; & & nbsp; & & nbsp & nbsp & nbsp; & & nbsp; & & nbsp & nbsp & nbsp; & nbsp; & & nbsp & nbsp & nbsp; & & nbsp & nbsp; & & nbsp & nbsp; & & nbsp & nbsp; & & nbsp & nbsp & nbsp; & & nbsp; & & nbsp & nbsp; & & nbsp; & & nbsp & nbsp & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; &Nbsp; & nbsp; & nbsp; & nbsp; 125x = 15 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 5 A: they have to work together for 5 days

A factory plans to produce a batch of parts, 12 people work 6 hours, completed 60% of the plan, according to this calculation, the remaining 20 people do, how many hours?