Solution: b is regarded as a multiple of 1
Then b originally had102/(2.4+1) =102/3.4 = 30 kg.
A originally 102-30 = 72kg.
2. Two schools, A and B, donated money to the farmers who suffered from the flood. Two schools donated 3600 yuan, of which 65438+B from school A+0.5 times from school B.. How much did a school donate?
Solution: If B is regarded as a multiple of 1, then the donation from school B is 3600/(1.5+1) = 3600/2.5 =1440 yuan.
A school donated 3600- 1440=2 160 yuan.
Xiaohua brought some money to buy exercise books. I bought two books, but I still have 1.8 yuan, and I bought four books, but I still need 2.4 yuan. Solution: How much money did Hua bring?
Each book is set at one yuan.
Then 2a+ 1.8=4a-2.4.
4a-2a= 1.8+2.4
2a=4.2
a=2. 1
Each copy is 2. 1 yuan.
Use 2. 1×2+ 1.8=6 yuan.
Arithmetic: (1.8+2.4)/(4-2) = 2.1yuan.
Use 2. 1×2+ 1.8=6 yuan.
4. In order to recover funds, a store in 480 yuan sells both A and B commodities. It is known that the added goods earned 20%, and the goods B lost 20%. What is the profit and loss result of the store?
The cost price of the two commodities is
480/( 1+20%)+480/( 1-20%)
=400+600
= 1000 yuan
1000-480*2=40 yuan
Lose 40 yuan
At the same time, two trains depart from Party A and Party B relatively. The speed of the express train is150km, and the speed of the local train is 90km. They meet at a distance of 240 kilometers from the midpoint. How many kilometers is it between Party A and Party B?
Solution: the express train runs more than the local train 150-90=60 km/h.
Then the express train is 240×2=480 kilometers longer than the local train.
Meeting time =480/60=8 hours
Distance between Party A and Party B = (150+90) × 8 =1920km.
There is a circular swimming pool in the park. Grandpa runs around the swimming pool 20 times a day. If the radius of the swimming pool is 38 meters, how many meters does Grandpa Li Run swim every morning?
Solution: Run 2× 3.14× 38× 20 = 4772.8m every day.
7. The newly developed roller has solved a difficult problem of expressway in China. Front wheel radius 1.5m, 8 revolutions per minute. How many meters does the roller advance per minute?
Solution: Forward 2× 3.14×1.5× 8 = 75.36 m.
There are 360 red balloons and yellow balloons in the shop, of which 25% are red balloons and 24 are yellow balloons. The remaining red balloons and yellow balloons are just equal. How many red balloons and yellow balloons are there?
Solution: 24 yellow balloons were sold, leaving 360-24=336.
At this time, the yellow balloon is regarded as the unit of 1, so Red Balloon has 1/( 1-25%)=4/3.
Originally there were 24+336/(1+4/3) = 24+144 =168 balloons.
Originally there were 360- 168= 192 Le Ballon Rouge.
9. Two-fifths of the freight in a warehouse was originally shipped out, and then 8400 tons were brought in, 30% higher than the original. How many tons of original goods are there in the warehouse?
Originally regarded as 1 unit.
After 2/5 shipment, there is still 1-2/5=3/5.
So it is 8400/(1+30%-3/5) = 8400/0.7 =12000 tons.
10, there are two warehouses, warehouse A has 2000 bags of grain, and after taking out a quarter and putting it in warehouse B, the grain in the two warehouses is equal. How many are A and B?
Solution: A takes out 2000× 1/4=500 bags.
Then at this time A has 2000-500= 1500 bags.
B There used to be 1500-500= 1000 bags.
A There were 2,000 bags.
1 1, Xiaoming and Xiaohua each have a few dollars, and Xiaoming has more money than Xiaohua by 85 yuan. After they both went to 30 yuan, Xiaoming had twice as much money left as Xiaohua. How much money do they each have?
Solution: Let Xiaohua have one yuan, then Xiaoming has a +85 yuan.
According to the meaning of the question
(a-30)×2=a+85-30
2a-60=a+55
A= 1 15 yuan.
Xiao Mingyou 1 15+85=200 yuan.
12. There is a rectangle. If its length and width are increased by 8 cm each, the area will increase by 208 cm 2. It is known that the length of the original rectangle is 6 cm longer than the width. What is the area of the original rectangle?
Solution: if the width is a, then the length is a+6 cm.
Just draw it and you will know.
8a+8*(a+6)+8*8=208
8a+8a+ 1 12=208
16a=96
A=6 cm
Length = 6+6 =12cm
Area = 12×6=72 cm2.
13, A and B *** 140 yuan, A bought a book and used up 4/7 of his money. At this time, the money left by the two is the same. How much did Party A and Party B originally have?
Solution: Take the amount of armor as the unit 1.
Then the money brought by B is 1×( 1-4/7)=3/7.
So a originally had140/(1+3/7) =140/(10/7) = 98 yuan.
B The original money was 140-98=42 yuan.
14, the store shipped 9/ 10 tons of sugar, sold this batch of sugar 1/3, and sold 1/3 tons of sugar. * * * How many tons of sugar did you sell?
Solution: * * Sell 9/10×1/3+1/3 = 3/10+1/3 = 9/30+130 =
15. beautify the campus. Put 120 potted flowers in front of the campus in the sixth grade. The fifth grade puts one-sixth less potted flowers in front of the building than the sixth grade. How many potted flowers are there in the second grade?
Solution: The quintic pendulum is120× (1-1/6) =120× 5/6 =100 pots.
Two grades, one * * * pendulum 120+ 100=220 pots.
16, 200 fry per square meter, how many can be stocked? Upper bottom: 30 Lower bottom: 80 Height: 90
It can raise 200×1/2× (30+80 )× 90 =100×10× 90 = 990000.
17, Xiao Ming made a small red flag of a right triangle with red paper. It is known that red paper is 12 decimeter long and 8 decimeters wide. The two right-angled sides of the small red flag are 2 decimeters and 3 decimeters respectively. How many small red flags can a piece of red paper make?
Solution: Together, the two small red flags are a rectangle with a length of 3 cm and a width of 2 cm.
So we can make 2×(8/2)×( 12/3)=2×4×4=32 faces.
18, rectangular box, length 17 cm, width 1 1 cm, height 2.2 decimeters. How many square centimeters should I pack this food box?
Solution: Need17×11× 2+(17+1)× 2× 22 = 374+1232 =1600.
2.2 decimeter =22 cm
19. Make 50 medical boxes (with covers) with plastic plates for earthquake relief medical personnel. Length 50 cm, width 20 cm and height 15 cm. How many square centimeters of plastic board do you need at least?
Solution: each needs 50× 20× 2+(50+20 )× 2×15 = 2000+2100 = 4100cm2.
A * * * needs 4 100×50= 105000 square centimeters.
20. The recycling box of the school environmental protection team is a rectangular iron box (with a cover), and the bottom of the box is a square with a circumference of 28 decimeters and a height of 5 decimeters. How many square meters of iron does it take to make a 10 recycling bin?
Solution: Bottom length =28/4=7 decimeters.
Each piece of iron needs 7×7×2+28×5=238 square decimeters.
A * * * needs iron sheet 238× 10=2380 square decimeter =23.8 square meters.