According to "1 bag of rice is equal to the weight of 2 bags of flour", we can try to change the weight of 50 bags of flour into the weight of rice (50÷2 = 25, and the weight of 50 bags of flour is equivalent to the weight of 25 bags of rice), so this question only leaves the amount of 1 bag of rice, 1 bag of rice.
2250(20+50÷2)= 50 (kg)
You can also change the weight of 20 bags of rice into the weight of flour, and find the weight of 1 bag of flour, and then find the weight of 1 bag of rice. It can be calculated as follows:
2250(20×2+50)= 25 (kg) 25×2 = 50 (kg)
2.
Solution: Let the price of each pen be X.
Because 12÷2=6 18÷3=6.
So 12 pen is as expensive as 18 ballpoint pen.
57.6÷2=28.8 (yuan)
12X=28.8 X solution: 2.4 (yuan)
And because the price of two pens is as much as that of three ballpoint pens, 2.4×2=4.8 4.8÷3= 1.6 yuan.
A: 2.4 yuan for each pen, ballpoint pen 1.6 yuan.
3.
Solution: make bananas x yuan.
5x=4(0.4+x)
5x= 1.6+4x
x= 1.6
A: Bananas per kilogram 1.6 yuan.
4.
There are x chickens. 2x+4(29-x)=92
x= 12
Only 29- 12= 17
12 chicken and 17 rabbit.
5.
Set the number x to 5 points,
Then 5x+4(2 1-x)= 100.
x= 16
6.
Suppose it's all 2 cents.
36*2=72 (point) 99-72=27 (point)
5-cent coin: 27/(5-2) = 9 (pieces)
2-cent coin: 36-9=27 (pieces)
7.
Let's assume that 20 stamps are 4 cents each, which will be worth 80 cents.
There is a difference of 20 points between 1 yuan, so if you change a 4-cent stamp into an 8-cent stamp.
It will make up the difference of 20 points to 4 points, so you need to change 5 4-point stamps into 8-point stamps.
So there are five 8-cent stamps and 15 4-cent stamps.
Or set up an X ticket that can buy 4 points. You can buy 8-cent porn. X+Y=20.4X+8Y= 100, and X= 15 can be obtained. Y=5。
8.
The answer is: 5/9
Suppose you bought X tickets for A and 50 tickets for B.
Equation 0.5*x+0.35*(50-x)= 19.6.
The solution is x= 14.
That is, A has 14 votes, and B has 50- 14 votes = 36 votes.
The money spent on buying tickets = 0.5 *14 = 7; B =0.35*36= 12.6.
7/ 12.6=5/9 is the ratio of money A to money B.