Xiaoming's family used 85 kilowatt hours of electricity last month, and the price per kilowatt hour was 0.412 yuan. There are five people in Xiaoming's family. How much is the average electricity charge per person? The distance from Jinan to Chengdu is 1650 kilometers, and the plane can reach it in 2.2 hours. After the train speed is increased, it will travel 150 kilometers per hour. How many times is the speed of the plane as that of the train? A classroom is 11.5 meters long and 7.5 meters wide. How many floor tiles should I buy at least if I want to lay a square floor tile with a side length of 0.5 meters?

Xiaoming's family used 85 kilowatt hours of electricity last month, and the price per kilowatt hour was 0.412 yuan. There are five people in Xiaoming's family. How much is the average electricity charge per person? The distance from Jinan to Chengdu is 1650 kilometers, and the plane can reach it in 2.2 hours. After the train speed is increased, it will travel 150 kilometers per hour. How many times is the speed of the plane as that of the train? A classroom is 11.5 meters long and 7.5 meters wide. How many floor tiles should I buy at least if I want to lay a square floor tile with a side length of 0.5 meters?

1. Total electricity cost of xiaomingjia = 0.412 * 85 = 35.02 yuan
The average electricity charge per person = 35.02/5 = 7.04 yuan
2. Aircraft speed = 1650 / 2.2 = 750 km / h
The speed of an airplane is five times that of a train
3. The number of floor tiles required is:
11.5*7.5/(0.5*0.5)=345
It costs 345 yuan

The laws of algebraic sum are as follows
(1) Calculation 1 + 2-3-4 + 5 + 6-7-8 +... + 2009 + 2010-2011-2012
(2) If we arbitrarily add the +, - sign before the number of 1,2,3,..., 2012, and then sum them, will the result be odd or even?
Fill in the blanks:
If a

1 = - 4-4-4-4. - 4 = 2010 divided by 4 times negative 4 = - 2010
2 = even
3.b

It is proved that if a is not equal to 0, the equation ax-b = O has only one real root

Suppose that the equation has two unequal real roots, X1 and X2, then
Ax1-b = 0, and ax2-b = 0
A (x1-x2) = 0,
And x1 ≠ X2, so a = 0
It is contrary to the proposition a ≠ 0, so the hypothesis is not true
The original proposition holds
It's over