Suppose the rest can be shipped x times. Then,
1/ 1600×20×20+ 1/ 1600×(20+30)x = 1
0.25+ 1/32x= 1
x=24
A: We can deliver the goods after the remaining 24 times.
2.( 1) Suppose two cars meet after x hours. Then,
57x+(57+ 1)x=276
x=2.4
A: After 2.4 hours, the two cars met.
(2) Assuming that it took y hours from the beginning to the distance of 46 kilometers, then,
57x+(57+ 1)x=276-46
x=2
A: The distance from the beginning to 46 kilometers took two hours.
(3) It is 69 kilometers from the beginning to the meeting, and it took Z hours * * *, then,
57x+(57+ 1)x=276-69
x= 1.8
A: It was 69 kilometers from the beginning to the meeting, and it took * * * 1.8 hours.
3.200 ÷10 = 20km/h
120 ÷10 =12km/h
20-12 = 8km/h
8×2 = 16 km/h (this is the speed in still water)
320÷ 16 = 20 hours (hours)
A: It took him 20 hours to sail 320 kilometers in calm water.
4. If the distance between Station A and bilibili is X kilometers, then
(x-65)÷65×58.5=x- 104
x=455
A: The distance between Station A and bilibili is 455 kilometers.
If you don't understand the third or fourth question, please add my qq to 1428289052.