A quadratic equation can also be used 400 lanes

A quadratic equation can also be used 400 lanes

Alas! My brother is a little late

This is an application problem ~ please make a formula calculation (the problem is below)
Party A and Party B jointly buy lottery tickets. In this period, Party A contributes 300 yuan and Party B 500 yuan. As a result, they won the first prize, with a total bonus of 10000 yuan. One fifth of the bonus is for personal income tax. How much yuan can party A and Party B get?

What is the ratio of Party A and Party B's contribution
300：500＝3：5
The bonus is
10000 × (1-1 / 5) = 8000 yuan
A get
8000 (3 + 5) × 3 = 3000 yuan
B get
8000 (3 + 5) × 5 = 5000 yuan

There are three chemical calculation problems
How many grams of 30% H2SO4 and water are needed for 20 g of 20% H2SO4 solution? How many grams of 10% NaCl and solid NaCl are needed for 200 g of 20% NaCl solution? How many grams of 10% H2SO4 and 40% H2SO4 are needed for 200 g of 20% h2so44 solution?

1. Need 30% H2SO4 20g * 20% = x * 30% = 40 / 3 g water 20g-40 / 3 g = 20 / 3G
2. 10% NaCl x * 10% + 200g-x = 200g * 20% x = 1600 / 9g, solid NaCl 200g-1600 / 9g = 200 / 9g
3. It needs 10% H2SO4 x * 10% + (200g-x) * 40% = 200g * 20% x = 400 / 3 g
40% H2SO4 200 G-400 / 3 g = 200 / 3 G

Formula of accounting calculation
At the beginning of 1991, an enterprise obtained a loan of 10 million yuan from the bank. It is stipulated that the loan should be paid off at the end of each year from the end of 1994 to the end of 2000 (the annual interest rate is 10%). How much should be paid off each year?

From 1991 to the beginning of 1994, the sum of the principal and interest of this loan is 10 million times (1 + 0.1) cubic. It is stipulated that the repayment time from the end of 1994 to the end of 2000 is seven years. According to the following formula, the annual repayable amount is X
X times pvif (0.1,7) = 10 million times (1 + 0.1) cubic. Can solve the value of X, pvif is the compound interest present value coefficient, pvif (0.1,7) can find out the specific value through the compound interest present value coefficient table, it is not convenient to calculate, so the calculation part is left to you to complete

Sixth grade mathematics application problem... (only the formula does not calculate, the column synthesis formula) urgent.. helps!
The length, width and height of a cuboid are 10cm, 8cm and 6cm respectively. Now cut the length, width and height of the cuboid by 1 / 4, and find out how many parts of the cuboid are cut off?

After cutting 1 / 4, the length is: 10-10 * 1 / 4 = 7.5cm
Width: 8-8 * 1 / 4 = 6cm
Height: 6-6 * 1 / 4 = 4.25cm
The volume of the original cuboid: 10 * 8 * 6 = 480 cubic centimeters
Now the cuboid volume: 7.5 * 6 * 4.25 = 191.25 cubic centimeters
（480-191.25）/480=3/5

If the product of three consecutive even numbers is 192, what is the largest number?

x(x+2)(x+4)=192
In the solution, only even number x = 4 is taken
The largest number is x + 4 = 8

Among the five consecutive even numbers, the product of the first and the fifth is 308
3Q~

5、
Let the first even number be x, then the fifth is x + 8
X*（X+8）=308
（X+4）^2=324
X=14
Then 5 even numbers are 14,16,18,20,22

The product of three consecutive even numbers is 48 times of the largest even number. What is the product of these three even numbers?

48=2³×3
therefore
48÷6=8
The three even numbers are: 6, 8 and 10
The product is: 6 × 8 × 10 = 480

In the 1988 natural numbers 1,2,3..., 1988, add a plus or minus sign between every two adjacent numbers. The result of this expression is even. Why?

The parity of the result is not related to the plus and minus sign, only to the plus and minus sign
The number of odd numbers,
In 1988, there are two
1988 △ 2 = 994 odd numbers
The sum of even and odd numbers is even

In the 1988 natural numbers 1,2,..., 1988, why is the result even if a plus or minus sign is added between every two adjacent numbers
Such as the title

Ignore even addition and subtraction directly, because even addition and subtraction result is even. Consider odd directly, odd addition and subtraction must be odd, even addition and subtraction is even. Obviously, 1988 can be divided by 4, so there are even odd items, so the answer is even