1, make a batch of clothes, A will finish it in 8 days, B will finish it in 10 day, and B will finish it in 1 day after two teams cooperate for a period of time. How many days did the two teams work together?

(1-110) ÷ (1/8+110) = 4 (days)

2. Two cars, A and B, set off from AB and go in opposite directions. When A travels 2/7 of the distance to B, B exceeds the midpoint by 30 kilometers. At this time, car A travels 45 kilometers more than car B. How many kilometers are there between AB?

(30+45) ⊙ (1/2-2/7) = 350 (km)

Xiao Lin has 36 stamps, Xiaoxin's stamps are 5/6 of Xiao Lin's and Xiaoming's stamps are 5/3 of Xiaoxin's. How many stamps does Xiaoming have?

36× 5/6× 5/3 = 50 (sheets)

4.A car travels from A to B, and when it reaches the whole journey, it is still 400 kilometers away from B. It is known that it takes 8 hours for this car to complete the journey. What is the average speed of this car?

The topic "When you arrive at the whole journey" is incomplete and cannot be answered.

A certain place was flooded, and the grain harvest was 30% less than last year. Last year, the grain output in this area was 7200 tons. How many tons of grain are there this year?

7200× (1-3/10) = 5040 (ton)