2. (5 points) if a batch of military materials is transported by 8 large trucks, it can be transported in 3 days. If it is transported by 5 small trucks, 25% of the total can be transported in 8 days. Now, 3 trucks are used

2. (5 points) if a batch of military materials is transported by 8 large trucks, it can be transported in 3 days. If it is transported by 5 small trucks, 25% of the total can be transported in 8 days. Now, 3 trucks are used

Crane efficiency = 1 / 8 / 3 = 1 / 24
Car efficiency = 75% △ 5 △ 8 = 3 / 160
Cooperation = 1 ÷ (3 × 1 / 24 + 4 × 3 / 160) = 5 days
Why do I count 80, 80, 80, 90, 90, 70, 70, 100, 100 in my homework as ten and classify them as nine?
But I know,
This is the number of nine
Three 80, two 90, two 70, two 100
Why do I count nine
On a straight road, there are two places, AB, 150 km apart. Two patrol cars, a and B, start from ab at the same time and travel at a constant speed along the kilometer,
The second question is inequality
On a straight road, there are two places a and B, which are 150 kilometers apart. A and B patrol cars start from a and B at the same time, and drive to B and a respectively at the same speed. The speed of a and B patrol cars is 70 km / h and 80 km / h respectively, and the driving time is set as X hours
(1) How many kilometers is the distance between the two cars before they meet? (the result is expressed in an algebraic expression with x)
(2) It is known that both cars are equipped with walkie talkies, and each walkie talkie can talk to each other within 15 km (including 15 km). How long can the two walkie talkies keep talking during driving?
Solution (1)
150-(70+80)x
=150-150x
The distance between the two cars is (150-150x) km from the start to the time when they meet
(2) : suppose that the longest talk time of two cars before meeting is y hours during driving, then the longest talk time of two cars after meeting is also y hours, and the longest talk time of two walkie talkies during driving is 2Y hours
(70+80)y≤15
150y≤15
y≤1/10
2y≤1/5
A: the longest time that two walkie talkies can talk is 1 / 5 hour
1）150-150x
2) 30 ÷ (70 + 80) = 0.2 hours
Please complete the title
(1) Because the distance is getting closer, so the distance is 150 - (70 + 80) X. of course, here is X
There are 66 tons of coal to be transported from the coal yard to the power plant. It is known that the carrying capacity of large trucks is 5 tons, and that of small trucks is 2 tons. They consume two times of fuel each time
It's 11L and 15L. How many large and small trucks are used to transport coal, so as to minimize the total fuel consumption? At least how much is needed? To calculate the formula process, try to use the method that pupils can understand
It takes 15 / 5 = 3L oil to transport a ton of coal by large truck
The average consumption of a ton of coal transported by a small truck is: 11 / 2 = 5.5L oil
So the efficiency of large trucks is high, so it should be transported by large trucks as far as possible
66 / 5 = 13, more than 1,
So use 13 big trucks to transport 65 tons, the remaining 1 ton with a small truck, the most fuel consumption
The total fuel consumption is: 13 * 15 + 11 = 206 L
1. How much is 4 / 5 of a number less than 2 / 5 of 45? 2. The number more than 80% of a number is 45.6
This number is less than 5 / 4 5 / 4 5 / 4 5 / 4 5 / 4 5 / 4 5 / 4 5 / 4 5
A and B depart from AB and go to C at the same time. It is known that the distance between AC and BC is 150 and 250 respectively. A calls B after 20 minutes and learns that B has driven for 30 minutes
1) What's the speed ratio between a and B?
2) Can a and B reach C at the same time? Why?
3) If we can't reach C at the same time, who should speed up and how much can we reach at the same time?
1 a speed: B speed = 20:30 = 2:3
2 can't arrive at the same time. Because according to the known speed ratio, when a arrives, B will arrive at 150 / 20 * 3 = 225
3, the speed becomes (250-30) / ((150-20) / 20) = 220 / 6.5 = 33.85
Therefore, the speed should be increased by 33.85-30 = 3.85
(1) Set: a speed: V1, B speed: v2
A calls B after 20 minutes and learns that B has driven for 30 minutes
They go at the same time:
20/V1=30/V2
V1/V2=2/3
(2) Let a arrive at T1 and B arrive at T2
T1=150/V1=225/V2
T2=250/V2
T1
There are 66 tons of coal to be transported from the coal yard to the power plant. It is known that the carrying capacity of large trucks is 5 tons, and that of small trucks is 2 tons. The fuel consumption of anmen is 11L and 5L respectively. How many large trucks and small trucks are used to transport coal to minimize the total fuel consumption? How much is the minimum?
If you want to use the least fuel, no car can be idle. That is, 12 large trucks and 3 small trucks use the least fuel. The fuel consumption is: 12 * 11 + 3 * 5 = 132 + 15 = 147 liters
This number should be counted
Count for me
My partner and I bought an excavator. The price of the excavator was 250000 yuan. I invested 200000 yuan and he invested 50000 yuan. At the end of 2008, we invested 89000 yuan in this excavator again and bought a long arm (the long arm originally agreed to invest 50% of each other, but the partner didn't have so much cash at that time, so I invested 89000 yuan alone. One month later, the partner transferred 50000 yuan to my account), He sold his long arm for 70000 yuan and shared 35000 yuan each
The project profit of this excavator up to now is 300000 yuan
Up to now, I have collected 279293 yuan (including 35000 yuan for selling long arm money and 50000 yuan transferred to my account by my partner one month later). I have spent 41401 yuan, that is to say, I have actually received 237892 yuan (279293-41401)
Recently, I plan to sell the excavator. If the excavator can sell 230000 yuan now, do I still have 184108 yuan receivable? If not, please help me calculate the amount receivable
Another point I don't understand is that the total investment of 250000 yuan for the excavator and 89000 yuan for the long arm is 339000 yuan, and the 50000 yuan transferred into my account by my partner is recorded in the accounting. The long arm is 89000 yuan, 50% of which is 44500 yuan. Is the 5500 yuan extra recorded in the money I have received? Or can it be recorded that I have invested 239000 yuan in total and the partner has invested 100000 yuan in total
Meishme thank you for your reply
Our profit share is not divided according to the proportion of investment. We negotiated that the profit share is 50% at the beginning, because most of the business is his. It can be understood that one person will pay more money and one person will contribute more. However, I will recover the extra funds first
My total investment is 200000 + 44500 = 244500
He invested 50000 + 44500 = 94500
If I make a profit, I'll take back the extra 150000 (244500-94500)
What's the 41401 yuan? It's the oil rebate I paid for the repair of the excavator. The above-mentioned project profit has deducted the daily expenses of me and my partner
How does the 50000 yuan transferred into my account by a partner enter into the account? This is a personal transaction between partners, not a partnership business. It is not recorded in the account. The 5500 yuan he transferred to you should be returned to him, not a partnership fund. When you invest 89000 yuan alone
A and B start from ab at the same time. When they meet for the first time, they are 120 km away from A. when they meet for the second time, they are 150 km away?
The second meeting was 150 kilometers away from a
Is the second encounter 150 kilometers away from a?
A and B met for the first time, a total of a whole line, a line: 120 kilometers
Party A and Party B meet for the second time, and they travel three whole distances. Party A should travel: 120 * 3 = 360 km
Suppose the length of the whole journey is x, then a will meet for the second time: 2x-150
So there are: 2x-150 = 360
X=255
That's 255 kilometers
How many times does a small truck need to carry 40 tons of goods?
15x40% = 6 tons (carrying capacity of small truck) 15x6 = 90 tons (total cargo) 90 △ 6 = 15 times