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For a project, Party A will do it alone in 15 days and Party B will do it alone in 20 days. After three days of cooperation between the two teams, team B will do the rest of the project alone. How many more days will it take to complete? -------------------------------------------------------------------- Please send the formula and solution to me if you know the answer,
[1-(1/15+1/20)×3]×20=13
A: it takes 13 days to complete it alone
1. The roller is a cylinder with a diameter of 2 meters and a length of 3 meters. How much area of road can it roll every week?
2. After taking out a conical metal part with a bottom diameter of 20 cm from a cylindrical tank with a bottom diameter of 40 cm, the water surface drops by 1 cm. What is the height of the conical metal part?
If you can tell the process and method of solving the problem, it will be better!
1, (2 / 2) ^ 2 * 3.14 * 3 = 9.42 square meters
2, (40 / 2) ^ 2 * 3.14 * 1 / [(20 / 2) ^ 2 * 3.14] = 400 * 1 / 100 = 4cm
Part height 4cm
The students held a 1-point rope skipping competition. The soldiers jumped 80 times. Lan Lan jumped 7 / 8 of the soldiers and 7 / 9 of Huan Huan. LAN LAN and Huan Huan jumped several times to find the formula. A rectangular container with a bottom of 3 decimeters long and 2 decimeters wide contained some water, The water surface has risen by 0.2 decimeter. What is the volume of this potato? The turnover of Hongqi supermarket in March was 300000 yuan, which is 1 / 5 higher than that in February. How many million yuan was the turnover in February
LAN 80 * 7 / 8 = 70
Huanhuan 70 / (7 / 9) = 90
Potato Volume 3 * 2 * 0.2
February 30 / (1 + 1 / 5)
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