20.07×39+200.7×4.1+40×10.035．

20.07×39+200.7×4.1+40×10.035．

20.07×39+200.7×4.1+40×10.035，=20.07×39+20.07×41+20×20.07，=20.07+（39+41+20），=20.07×100，=2007；

After one seventh of the price reduction, each refrigerator will sell for 840 yuan. The original price of each refrigerator is () yuan, but the price reduction is () yuan?

The original price of this refrigerator is (980) yuan, but the price is (140) yuan

A. B two cars leave from a and B at the same time. A's speed is 125% of B's. after the two cars meet, B will drive 20 hours to reach A. how many hours will they meet?

Speed ratio = inverse ratio of time
So VA: VB = 5:4
The time ratio is 4:5
Car B is 20 hours away, car a is only 20 * 4 / 5 = 16 hours
So when they met, it was 16 hours

7. After the price of a color TV has been increased by one seventh, it has been reduced by one seventh. The current price is higher than the original price (). A. expensive B. cheap C. the same

B

1. The students made 20 cylindrical lampshades with colored paper. Each lampshade is 35cm high and the circumference of the bottom circle is 47.1cm. How much colored paper do you need at least?
2. Calculate the body conditions of the following figures (see Figure)
3. How many cubic meters of coal do you need for a piece of honeycomb briquette? (keep the whole number) (see Figure)

1:35*47.1*20

The price of a refrigerator is 2100 yuan after 8% reduction. How much is the original price

2100*(8/7)=2400

1 + X / 0.1 minus 0.4x-0.5 / 0.2 = 1 / 2 to solve the equation (with process)

1+x/0.1-(0.4x-0.5/0.2)=1/2
1+x/0.1-0.4x+0.5/0.2=1/2
1+2.5-0.5=0.4x-x/0.1
3-0.4x=-x/0.1
0.1(3-0.4x)=-x
0.3-0.04x+x=0
0.96x=0.3
x=3.2

The original price of a refrigerator was 2400 yuan, but now the price is reduced by 1 / 8. How much is the price reduced?

One eighth of 2400 is 300

X ^ 2 + 4x = - 3 to solve the equation

x^2+4x = -3
x^2+4x+4=1
（x+2）^2=1
x+2=±1
X = - 1 or x = - 3

How much is the original price of a refrigerator when it is sold for 2100 yuan after 8% price reduction?

2100÷（1-1/8）
＝2100÷7/8
＝2100×8/7
= 2400 yuan