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The distance between port a and port B is 360 km. It takes 35 hours for a ship to go back and forth. It is 5 hours faster along the water than against the water. At present, the speed of a motorboat in still water is 12 km per hour. What is the time for it to go back and forth between the two ports?
(35-5) △ 2 = 15 = 30 △ 2 = 15 (hour) 35-15 = 20 & nbsp; (hour) (360 △ 15-360 △ 20) △ 2 = (24-18) △ 2 = 6 △ 2 = 3 (kilometer) 360 △ 12 + 3) + 360 △ 12-3) = 360 △ 15 + 360 △ 9 = 24 + 40 = 64 (hour). A: it takes 64 hours to travel between the two ports
For a project, Party A and Party B cooperate for six days, and Party B and Party C cooperate for 10 days. Now, Party A, Party B and Party C cooperate for three days, and the remaining Party B works for another six days. How many days does it take for Party B to complete the project alone?
1、
Party B completes (1-3 / 6 + 3 / 10) / (6-3) = 1 / 15 of the total amount every day
It takes 15 days for Party B to complete it alone
A: it takes 15 days for B to finish it alone
2、
The original length is 10 (2 / 3-5 / 9) = 90cm
The original width is 90x2 / 3 = 60cm
The original rectangular cloth area is 90x60 = 5400 square centimeters
A: the original rectangular cloth area is 5400 square centimeters
1. The surface area of a cube is 24 square decimeters, and the area of each side is_____ Square decimeter, edge length is______ DM, the volume is_____ Cube decimeter. 2. Cut a cube with an edge length of 1 decimeter into a small cube with an edge length of 1 centimeter, and arrange them in a row. How many meters can you arrange?
The first question: the first empty: cube has six faces, so 24 △ 6 = 4;
The second space: the cube has 12 edges and they are all equal, so 24 △ 12 = 2,;
The third space, after knowing the edge length, can find the volume: 2 * 2 * 2 = 8;
Question 2: because 1 decimeter = 10 cm, the volume of cube with edge length of 1 decimeter is 10 * 10 * 10 = 1000 cubic centimeter. There are 1000 cubes with edge length of 1 cm in 1000 cubic centimeter, so a row is 1000 cm = 10 m, the answer is 10 m
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