A businessman will first increase the original price of color TV by 40%, and then write in the advertisement "big reward, 20% discount". The result is that each color TV makes 270 yuan more than the original price, then the original price of each color TV is______ Yuan

A businessman will first increase the original price of color TV by 40%, and then write in the advertisement "big reward, 20% discount". The result is that each color TV makes 270 yuan more than the original price, then the original price of each color TV is______ Yuan

Suppose the original price of each color TV is x yuan, then: (1 + 40%) x × 0.8-x = 270, the solution is: x = 2250, so the answer is: 2250

The area of a rectangle is 40 square meters, the length is 8 decimeters, the width is several decimeters? What is the perimeter of the rectangle?

500 decimeters, perimeter 1016 decimeters

Calculation: 1-3 + 5-7 + 9-11. + 2007-2008=

There is something wrong with this formula
The front items are all odd. Where did the last 2008 come from?
And even if 2008 is 2009, it should be - 2007 + 2009 in the end
And 1-3 + 5-7 + 9 - -2007+2009=（-2）*502+2009=1005

A train is 120 meters long. It takes 20 seconds for the whole train to pass the 480 meter railway bridge. How many meters does this train travel per second
can't

36m

The perimeter of a rectangle is 140 cm. The ratio of its length to width is 5:2. How many square centimeters is the area of a rectangle?
The ratio of number a to number B is 3: the ratio of number a to number C is 6: the sum of their three numbers is 420

140 △ 2 = 70 (CM)
Length: 70 × 5 / (5 + 2) = 50 (CM)
Width: 70 × 2 / (5 + 2) = 20 (CM)
Area: 50 × 20 = 1000 square centimeter
A: B = 3:5 = 6:10
A: C = 6:5
Therefore, a: B: C = 6:10:5
So a: 420 × 6 / (6 + 10 + 5) = 120
B: 200
C: 100
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Let f {x} = log2x-logx4 {0 ＜ x ＜ 1}. The general term an of the sequence {an} satisfies the an power of F {2} = 2n
Find the general term formula of sequence {an}

F {an power of 2} = log2 * (an power of 2) - an power of log2 4, {0 < x < 1} = An-2 / an = 2n
An ^ 2-2an * n-2 = 0, an ^ 2-2an * n + n ^ 2 = 2 + n ^ 2, an = (2 + n ^ 2) ^ 1 / 2-N, or an = - (2 + n ^ 2) ^ 1 / 2-N, because 0

Xiao Ming takes a taxi to his aunt's home, which is 7.5 kilometers away from home. If he takes a taxi for 3 kilometers, he will charge 3 yuan. If he takes a taxi for more than 3000 meters, he will add 1.8 yuan per kilometer. Is 10 yuan enough for Xiao Ming?
Write the formula,

7-3 4 1.8*2 0.9 1.8+1.8+1.8+1.8+0.9 8.1

As shown in the figure, in the pyramid p-abcd, the bottom is a right angle trapezoid, ad ‖ BC, ∠ bad = 90 °, PA ⊥ bottom ABCD, and PA = ad=
As shown in the figure, in the pyramid p-abcd, the bottom is a right angle trapezoid, ad ‖ BC, ∠ bad = 90 °, PA ⊥ bottom ABCD, and PA = ad = AB = 2BC, m and N are the midpoint of PC and Pb respectively
Finding the volume of (1) pyramid p-abcd
(2) Verification of Pb vertical DM
(3) Finding Admn area of cross section

The volume of p-abcd is 1 / 3SH = 1 / 3 (AD + BC) × ab △ 2 · AB because the bottom is a right angle trapezoid with AD ‖ BC, ∠ bad = 90 ° and PA ⊥ bottom ABCD. The volume of p-abcd is 1 / 3 (AD + BC) × ab △ 2 · AB = 2BC ^ 32 because PA = ad = AB = 2BC

What does the fourth power of (- 5) mean?

The fourth power of (- 5) = 5 ^ 4 = 625
-The fourth power of 5 = - 5 ^ 4 = - 625

A taxi company has 100 taxis, and the average daily gasoline cost of each taxi is 80 yuan. In order to reduce environmental pollution, the market introduces a device called "CNG" to convert gasoline to natural gas, and the price of each taxi is 4000 yuan. After the company refits some vehicles for the first time, it calculates that the daily fuel cost of the refitted vehicles accounts for the daily fuel cost of the remaining unmodified vehicles Q: (1) how many taxis has the company refitted? How much is the average daily fuel cost of each taxi after modification lower than that before modification? (2) If the company refits all taxis at one time, how many days can it recover the cost from the saved fuel cost?

(1) Suppose that the company refits y cars for the first time, and the fuel cost of each taxi after refitting is reduced by X. according to the meaning of the problem, the equations are as follows: 80 (1 − x) y = 320 × 80 (100 − y) 2Y × 80 (1 − x) = 25 × 80 (100 − 2Y). The solution is x = 25 = 40%, y = 20