Students in Grade Two should work X hours.
( 1/7.5)+( 1/5)x = 1
x= 10/3
* * * It takes 10/3+ 1=4 and 1/3 hours.
2. A rides a bike from place A to place B, and B rides a bike from place B to place A, both of which advance at a uniform speed. It is known that they set off at 8: 00 a.m. at the same time, with a distance of 36 kilometers from 10 in the morning and 12 at noon. Find the distance from AB to the city.
Suppose the AB distance is x, when 12-10 =2 hours and when 10 -8 hours =2 hours.
2*[(36*2)/2]=X-36
The first two hours are from 8: 00 to 10, ***2 hours.
36*2 is from 10 to 12, which is 36 kilometers apart, that is, two people walked 36 * * 2 kilometers in two hours.
(36*2)/2 Find how many kilometers two people walk in an hour, which is the sum of their speeds.
According to the sentence "Know that two people start at 8 o'clock in the morning at the same time, and in the morning 10, they are still 36 kilometers apart", the equation is listed.
result
X= 108
A: The distance between AB is 108km.
A train from 3 A to B runs at a speed of 90km/h, and it is delayed 12 minutes. After the train accelerated to 10 km/h, it just arrived at B on time. How to find the distance between a and b?
Solution: If the distance between Station A and bilibili is S kilometers, there are:
S/90 =(S/2)/90+ 12/60+(S/2)/(90+ 10)
Solution: S=360 (km)
A: The distance between Party A and Party B is 360 kilometers.
Xiaoming went to his grandmother's house. If he walks 5 kilometers an hour, he will arrive at the scheduled time. When he walked a fifth of the distance, he got on a bus with a speed of 40 kilometers per hour, so he arrived 24 minutes earlier than scheduled 1 hour. What is the distance between Xiaoming and his grandmother's house?
Solution: If the distance between Xiaoming and his grandmother's house is S kilometers, there are:
S/5 =(S/5)/5+(4S/5)/40+( 1+24/60)
Solution: S= 10 (km)
A: The distance between Xiaoming and his grandmother's house is 10 km.
Try to practice by yourself. Wish you success! Happy new year!
1. A company plans to travel somewhere. The company is planning to contact travel agencies A and B. The cost of each travel agency is 300 A, and the travel agency said that all of them will be 20% off. Travel agency b says one person is free and the rest is 10% off. Given the number of companies, is the total cost of the two travel agencies the same?
2. The scores of Chinese, mathematics and foreign languages in Zhao Gang's final exam are three consecutive even numbers, with a total of 270. What's your math score?
3. Now a commodity is reduced in price 10% for promotion. In order to keep the total sales amount unchanged, how many percent will the sales volume increase over the original price?
Party A said to Party B, "When I was your age, you were only 4 years old." Party B said to Party A, "When I reach your present age, you will be 6 1 year old." What are the ages of Party A and Party B now?
For a batch of manuscripts, if Party A finishes copying in 30 hours, Party B finishes copying in 20 hours, and 3 hours later is the remaining time for Party B to finish copying. How many hours does Party B need to copy?
6. Party A and Party B set off from AB for a place by motorcycle, which is 60 kilometers apart. Party A is behind Party B. Party A rides 80 kilometers per hour and Party B rides 45 kilometers per hour. If Party A leaves 30 minutes earlier than Party B, how long will it take for Party A to catch up with Party B?
7. An airplane was originally scheduled to fly to its destination at a speed of 495 kilometers per hour, but due to the urgent task, its flight speed was increased to 660 kilometers per hour, and it arrived 1 hour earlier. What is the total flight distance?
8. Eat 0.6 kg of soy sauce first, then eat the remaining 3/5, and there is 0.8 kg of soy sauce in the bottle. How many kilograms is this bottle of soy sauce?
9. A truck and a bus walk with their backs to each other at the same time. When the truck travels for 5 hours and the bus travels for 6 hours, the distance between the two cars is 568 kilometers. As we all know, trucks are 8 kilometers faster than buses every hour. How many kilometers does this bus travel per hour?
10, Xin Li rode a bike and Liu Qiang rode a motorcycle. At the same time, they started from two places 60 kilometers apart and walked in opposite directions. After meeting on the road, move on and turn your back. Six hours after their departure, they were 240 kilometers apart. As we all know, the speed of Xin Li is18km. How many kilometers does Liu Qiang drive every hour?
1 1, Party A and Party B are 22.5km apart, and walk in opposite directions at the speed of 2.5km/h and 5km/h respectively. At the same time, the puppy brought by Party A ran to Party B at a speed of 7.5km/h, and the puppy returned to Party A immediately after meeting Party A, and then ran to Party B … until Party A and Party B met, the distance that the puppy should walk was calculated.
12, a car drove from a to b at a speed of 60 kilometers per hour. After driving for 4 hours and 30 minutes, the road skidded in the rain, so the car didn't drive fast and the speed was reduced by 20 kilometers per hour. As a result, it arrived at B 45 minutes later than expected, and the distance between A and B was found.
13, Grade 7 students went for a spring outing. If one bus is reduced, each bus will take exactly 60 people. If one bus is added, each bus can take exactly 45 people. How many students are there in Grade Seven?
14, Xiao Gang and Xiao Ming rode to the suburbs to play, and decided to leave home at 8 am in advance. It is estimated that they will ride at a speed of 7.5 kilometers per hour and arrive at their destination at 10 am. Before leaving, they decided to arrive at their destination at 9 am. So how many kilometers do you ride every hour?
15, a milk processing factory has 9 tons of fresh milk. If you sell fresh milk directly in the market, you can get 500 yuan per ton; Made into yogurt for sale, the profit per ton can reach 1200 yuan; Made into milk tablets for sale, the profit per ton can reach 2000 yuan. The production capacity of this factory is: making yogurt, which can process 3 tons a day; Made into milk tablets, it can be processed 1 ton every day. Limited by personnel, this batch of milk must be sold or processed within 4 days. Therefore, two feasible schemes are designed:
Option 1: Make as many pieces of milk as possible and sell the rest directly.
Option 2: Make part of it into milk slices and the rest into yogurt for sale, which will be completed in exactly 4 days.
Q: Which scheme do you think is more profitable? Why?