It takes 15 hours for Party A to produce a batch of parts by itself, while the work efficiency of Party B is 50% higher than that of Party A. Party B can complete the work in a few hours by itself and cooperate with each other in a few hours

It takes 15 hours for Party A to produce a batch of parts by itself, while the work efficiency of Party B is 50% higher than that of Party A. Party B can complete the work in a few hours by itself and cooperate with each other in a few hours


If the efficiency of a is 1 / 15, then the efficiency of B is 1 / 10, (1 / 15 * (1 + 50%) = 1 / 10). That is to say, B takes 10 hours to complete
The efficiency of a and B is 1 / 15 + 1 / 10 = 1 / 6



Party A, Party B and Party C work together on a batch of parts. It takes 6.5 hours for Party A to do it alone, 8 hours for Party B to do it alone, and 15 hours for Party C to do it alone. Whose work efficiency is higher


This is a simple engineering problem, work efficiency = total amount of work / working time
Method 1: assume that this batch of parts is "1"
The efficiency of a is: 1 / 6.5 = 2 / 19
The working efficiency of Party B is: 1 / 8 = 1 / 8
The working efficiency of C is: 1 / 15 = 1 / 15
2 / 19 > 1 / 8 > 1 / 15, so a fast
Method 2: this problem can be solved in proportion
The working time ratio of a, B and C is 6.5:8:15 = 19:16:30
The efficiency ratio is inversely proportional: 30:19:16
A fast



Manufacturing a batch of parts, according to the plan 18 days to complete its 12, if the work efficiency is improved after 3 days, then how many days will it take to complete this batch of parts in total?


(13 − 12 ﹣ 18 × 3) ﹣ 12 ﹣ 18 × (1 + 18)] + 3, = (13-136 × 3) ﹣ 12 ﹣ 18 × 98] + 3, = (13-112) ﹣ 136 × 98] + 3, = 14 ﹣ 132 + 3, = 8 + 3, = 11 (days), a: it takes 11 days to complete the 13 parts