For a section of highway, it will take 15 days for engineering team a alone, 20 days for engineering team B alone, and there are 2600 meters left after 3 days of construction by both teams. How many meters are there in this section of highway?

For a section of highway, it will take 15 days for engineering team a alone, 20 days for engineering team B alone, and there are 2600 meters left after 3 days of construction by both teams. How many meters are there in this section of highway?

Party A and Party B jointly repair for 3 days and complete all tasks:
（1/15+1/20）×3
=（4/60+3/60）×3
=7/60×3
=7/20
All tasks left: 1-7 / 20 = 13 / 20
All tasks are: 2600 △ 13 / 20 = 4000 meters
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To build a highway, team a needs 15 days to complete the construction alone, team B needs 12 days to complete the construction alone, team a needs 6 days to complete the construction first, and team a and team B need to build the rest together

1-1/15×6=3/5
3 / 5 ÷ (1 / 15 + 1 / 12) = 4 days
A: it will take four days for the joint repair

It will take 15 days for team a to build a road, 12 days for team B to build it alone, six days for team a to build it first, and the rest will be jointly built by team a and team B. how many days will it take for team a and team B to build it together?

(1-115 × 6) / (115 + 112) = (1-25) / (320 = 35 × 203 = 4 days) a: it will take four days for team a and team B to work together