Thinking: After 9+3 hours, the bus still needs 420 kilometers to run. The truck ran 12 hours, and there are still 300 kilometers to complete the whole journey, so the truck runs (420-300) ÷ 12 = 10 kilometers more than the truck every hour.
Solution: The bus does not run x kilometers per hour, and the truck runs (X+ 10) kilometers per hour.
(X+X+ 10)×9 = 12X + 420
X=55
Freight car speed 55+ 10 = 65 (km)
Distance between Party A and Party B (55+65)×9= 1080 (km)
There are some apples and pears. If a pile of/kloc-0 apples and 2 pears are divided, when the pears are divided, there are still 5 apples left. If you divide the apple into a pile of three apples and five pears, there will be five pears left when the apple is divided. So how many apples and pears are there?
Solution: If there are X apples, then the number of pears is (x-5) × 2.
X÷3 = [(X-5)×2-5]÷5
X=45
There are (45-5) × 2 = 80 pears.
3. Divide two numbers, quotient 3 is 10, sum of dividend, divisor and quotient is 163, dividend is (1 15), and divisor is (35).
The number of little red pencils is twice that of Xiao Ming. She took out 15 pencils and donated them to Project Hope, which is exactly half of the total number of little red pencils. How many pencils does Xiaohong have?
Thinking: "It is exactly half of the sum of Xiaohong and Xiaoming branches", that is to say, "Xiaohong and Xiaoming have as many branches".
Solution: Let Xiaoming have X pencils and Xiaohong have 2X pencils.
2X- 15=X
X = 15
Xiaohong originally had 15×2 = 30 (branch).
5. Three farms * * * feed 1600 cows. The second farm raises twice as many cows as the first farm, and the third farm raises twice as many cows as the second farm. How many cows are raised on each of the three farms?
Solution: If the number of cows raised on the second farm is X, then the first farm has (X÷2) cows.
The number of heads raised on the third farm is 2x+60.
2X+60 + X +(X÷2)= 1600
X = 440
The first farm has 440÷2=220 (heads).
The number of heads raised in the third field is 2× 440+60 = 940.
Buy 6 notebooks and 4 pens and pay 55.2 yuan. If you change all your notebooks into pens, you have to give them to 4.8 yuan. How much is each notebook?
(55.2+4.8) ÷ (6+4) = 6 (Yuan)
(55.2-6× 4) ÷ 6 = 5.2 (yuan)
A: Every notebook 5.2 yuan.
6. The usual price of eggs is 7 yuan, with a price increase of 10%. After restoring the original price, what is the price reduction ratio?
1-7÷(7× 1 10%)= 1/ 1 1=9. 1%
A: The price has been reduced by 9. 1%.
7.a and B install a pole every 45 meters, with 29 poles at both ends. Now, install 1 pole every 60 meters. Except for the two poles at both ends, how many poles will not move halfway?
Distance from AB to Beijing: 45×(29- 1)= 1260 (m)
The least common multiple of 45 and 60 is 180, so the pole does not move every 180 meters.
The fixed pole is: 1260÷ 180-2=5.
A: There are five still in the middle.
8. Ship A sails from place A to place B, and ship B sails from place B to place A. The two ships meet at the same time 10 hour, and then continue to drive for 3 hours. At this time, ship A is still 280 kilometers away from place B, and ship B is still 420 kilometers away from place A. How many kilometers are there between place A and place B?
Thinking: "A ship is 280 kilometers away from B ship, and B ship is 420 kilometers away from A ship" means the distance traveled by two ships (10-7) = 3 hours.
(280+420) ÷ (10-3) ×10 =1000 (km)
A: The distance between the two places is 1000 km.
9. Someone bought a batch of mechanical pencil at the price of 16 yuan, and then bought the same pens twice as much as the previous batch at the price of 2 1 yuan. If he wants to make a profit of 20%, how much should he sell them for three pens?
Solution: Suppose you buy X pieces for the first time, and then you buy 2x pieces.
* * * The total amount of currency used is (x÷ê3 )×16+(2x÷ê4 )× 21=16x yuan.
So the unit price of the stock is 16x÷3x= 16/3 (RMB per share).
To make a profit of 20%, the price of a single unit is16/3x1.2 = 6.4 yuan.
So selling 3 pieces is 6.4×3= 19.2 yuan.
A: It should be sold at the price of 3 pieces 19.2 yuan.
10, there are two cuboid containers, in which the water depth in container A is 48 cm (30 cm long and 20 cm wide), and part of the water in container A is transferred to container B (40 cm long and 30 cm wide), so that the height of water in the two containers is equal. How high is the water level at this time?
Solution: let the water height be x cm.
(20*30x+40*30x)=48*30*20
1800x=28800
x= 16
Answer: At this time, the water level is 16 cm.