For a batch of cement, team a finished it in 10 days, team B finished it in 15 days, and team C finished it in 20 days. Now the three teams are carrying it together at the same time, and team a transferred it halfway. As a result, it was completed in 6 days, and asked a few questions

For a batch of cement, team a finished it in 10 days, team B finished it in 15 days, and team C finished it in 20 days. Now the three teams are carrying it together at the same time, and team a transferred it halfway. As a result, it was completed in 6 days, and asked a few questions

A does 1 / 10 a day, B does 1 / 15 a day, C does 1 / 20 a day
Let a do it only for X days, then
x/10+6/15+6/20=1
Solution
x=3

For a batch of goods, it takes 10 days for team a to complete the transportation alone, and 15 days for team B to complete the transportation alone,
(1) After a few days of joint shipment, one third of the goods are left
2. After two days of joint transportation, the rest will be transported by team B alone. Can it be completed in eight days

1. 1 / 10 = 1 / 10 1 / 15 = 1 / 10 / 15 + 1 / 15 = 1 / 6 1 / 1-1 / 3 = 2 / 3 2 / 3 1 / 6 = 4 (days) a: 4 days later
2. 1 / 6 × 2 = 1 / 3 1-1 / 3 = 2 / 3 2 / 3 2 / 15 1 = 10 (days) 10 + 2 = 12 (days) a: can't complete

It takes five days for the construction site to carry away a pile of soil and 160 trucks of sand every day. Now, how many trucks should be transported every day

5 days: 160 vehicle sand / day * 5 days = 800 (vehicle sand);
Now it took four days to transport 800 cars of sand, so we should transport 800 cars of sand every day / 4 days = 200 cars of sand / day;