The cooperation between Party A and Party B is completed in one day 1 ÷ 2.4 = 5/ 12, and the payment 1800 ÷ 2.4 = 750 yuan.
The cooperation between ethylene, propylene and Fang Yitian is 1 ÷ (3+3/4) = 4/ 15, and the payment is 1500× 4/ 15 = 400 yuan.
The cooperation between Party A, Party C and Fang Yitian is 1÷ (2+6/7) = 7/20, and the payment is 1600× 7/20 = 560 yuan.
Three people cooperate in one day (5/12+4/15+7/20) ÷ 2 = 31/60,
Three people cooperate to pay (750+400+560) ÷ 2 = 855 yuan a day.
Party A alone completes 31/60-4/15 =1/4 every day, and pays 855-400 = 455 yuan.
Party B alone completes 3 1/60-7/20 = 1/6 every day, and pays 855-560 = 295 yuan.
Party C alone completes 31/60-5/12 =110 every day and pays 855-750 = 105 yuan.
So by contrast,
Choose b with 1 ÷ 1/6 = 6 days, only 295× 6 = 1770 yuan.
A rectangular iron block is placed in a cylindrical container. Now turn on the tap and pour the water into the container. In 3 minutes, the water surface is just above the top of the cuboid. In another 18 minutes, the water has filled the container. It is known that the height of a container is 50 cm and the height of a cuboid is 20 cm. Find the ratio of the bottom area of a cuboid to the bottom area of a container.
Divide this container into upper and lower parts. According to the time relationship, it can be found that the volume of water in the upper part is 18 ÷ 3 = 6 times that of the lower part.
The height ratio of the upper half and the lower half is (50-20): 20 = 3: 2.
So the bottom area of the upper part is 6 ÷ 3× 2 = 4 times the bottom area of the lower part filled with water.
Therefore, the ratio of the bottom area of the cuboid to the bottom area of the container is (4- 1): 4 = 3: 4.
Unique solution:
(50-20): 20 = 3: 2, and when there is no cuboid, it takes 18*2/3= 12 (minutes) to fill 20 cm.
So the volume of a cuboid is 12-3=9 minutes of water, because the height is the same.
So the volume ratio is equal to the bottom area ratio, 9: 12 = 3: 4.
5. Two bosses of Party A and Party B buy a piece of fashion at the same price, and Party B buys 1/5 sets more than Party A, and then Party A and Party B sell them at profit margins of 80% and 50% respectively. After both of them were sold out, A still made more profits than B, just enough for him to buy 10 this fashion. How many sets of this fashion A did you buy?
Consider that the number of groups of A is 5 and the number of groups of B is 6.
The profit earned by A is 80% × 5 = 4, and the profit earned by B is 50% × 6 = 3.
A is 4-3 more than B = 1 copy, and this1copy is 10 set.
So, A initially purchased 10× 5 = 50 sets.
6. There are two water pipes A and B, and water is injected into two pools with the same size at the same time. At the same time, the water injection ratio of A and B is 7: 5. After 2+ 1/3 hours, the sum of water injected into pools A and B is exactly one pool. At this time, the water injection rate of pipe A is increased by 25%, while the water injection rate of pipe B is unchanged. So, how many hours does it take for pipeline A to fill pool A and pipeline B to fill pool B?
Think of a pool of water as 1.
Because a pool of water was injected after 7/3 hours, 7/ 12 was injected into the A pipe and 5/ 12 was injected into the B pipe.
The water injection rate of a pipe is 7/ 12 ÷ 7/3 = 1/4, and that of b pipe is 1/4× 5/7 = 5/28.
The later water injection of a pipeline is1/4× (1+25%) = 5/16.
The time spent is 5/ 12 ÷ 5/ 16 = 4/3 hours.
It takes 1 ÷ 5/28 = 5.6 hours for tube B to fill the pool.
Water injection needs 5.6-7/3-4/3 = 29/ 15 hours.
That is 1 hour and 56 minutes.
Continue to do another method:
According to the original water injection rate, it takes 7/3 ÷ 7/ 12 = 4 hours to fill the pool with pipes.
The filling time of tube B is 7/3 ÷ 5/ 12 = 5.6 hours.
Time difference is 5.6-4 = 1.6 hours.
Later, the speed of nailing pipe increased, so the time was less and the time difference was more.
After the speed of A is increased, it takes 7/3× 5/7 = 5/3 hours.
The shortened time is equivalent to1-1÷ (1+25%) =1/5.
So the time is shortened by 5/3× 1/5 = 1/3.
So the second pipe needs1.6+1/3 = 29/15 hours.
Do it another way:
(1) The remaining nail tubes need time.
7/3× 5/7 ÷ (1+25%) = 4/3 hours.
(2) The time required to find the remaining B tubes.
7/3× 7/5 = 49/ 15 hours
(3) When the tube A is full, the tube B is evacuated.
49/ 15-4/3 = 29/ 15 hours
Xiao Ming walks from home to school in the morning. When he ran halfway, his father found that Xiao Ming's math book was left at home, and then he rode to deliver it to Xiao Ming. When catching up, Xiaoming still had 3/ 10 to go, so he got on his father's car and was sent to school by his father, so Xiaoming arrived at school five minutes earlier than he walked alone. How long does it take Xiaoming to walk from home to school?
The speed ratio between dad riding a bike and Xiaoming walking is (1-3/10): (1/2-3/10) = 7: 2.
The time ratio between cycling and walking is 2: 7, so it takes 5 ÷ (7-2) × 7 = 7 minutes for Xiaoming to walk 3/ 10.
Therefore, it takes 7 ÷ 3/ 10 = 70/3 minutes for Xiao Ming to complete the race.
8. Both A and B start from place A and pass through place B to place C. The distance between A and B is equal to the distance between B and C. The speed of car B is 80% of that of car A. It is known that car B starts earlier than car A 1 1 minute, but it stops at place B for 7 minutes, while car A continues to drive to place C. Finally, train B is faster than car A. Then car A will overtake car B a few minutes after car B leaves.
There are more cars B than A, 1 1-7+4 = 8 minutes.
It takes 8 ÷ (1-80%) = 40 minutes to display dealership B, and 40× 80% = 32 minutes to display dealership A..
It takes 40 ÷ 2+7 = 27 minutes for the second car to stop at point B.
A train arrives at B in 32 ÷ 2+ 1 1 = 27 minutes after B train leaves.
That is, catch up with the b car in b place.
9. Party A and Party B have two cleaning vehicles to clean the road between things. It takes 15 hours for car A to clean alone, and 15 hours for car B to clean alone. Two cars leave from East and West at the same time. When they met, car A cleaned more than car B 12 kilometers. How many kilometers is there between East and West?
The speed ratio between car A and car B is 15: 10 = 3: 2.
When they met, the distance ratio between car A and car B was also 3: 2.
Therefore, the distance between the two cities is 12 ÷ (3-2) × (3+2) = 60km.
100 is too much, that's all.