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2 / 9 × 3.6 = 1 / 4 × 3.6=
2/9x3.6=2/9x9x0.4=2x0.4=0.8
1/4x3.6=1/4x4x0.9=1x0.9=0.9
Question 7 on page 108 of the seventh grade mathematics book of Beijing Normal University Edition,
In the first quarter of a store, several A-type electrical appliances were sold according to the original price (cost + profit), with an average profit of 25% for each. In the second quarter, due to a slight increase in profit, the number of A-type electrical appliances sold was only 5% of that sold in the first quarter, but the total profit was the same as that in the first quarter
(1) Ask this counter to sell a kind of electrical appliances in the second quarter, what's the average profit per piece?
(2) In the third quarter, the counter sold type a electrical appliances at 90% of the price in the first quarter. As a result, the number of pieces sold increased by 1.5 times compared with that in the first quarter. What percentage of the profit of type a electrical appliances sold in the third quarter increased compared with the total profit of type a electrical appliances sold in the first quarter?
(1) Suppose the cost is a, the number of sales is B, and the profit margin in the second quarter is C
Then profit = a × 25% = 1 / 4A
Sales of 5 / 6B electrical appliances in the second quarter
Total profit in the first quarter = 1 / 4AB
Second quarter profit = AC × 5 / 6B = 5 / 6abc
According to the meaning of the title
1/4ab=5/6abc
c=1/4×6/5
c=3/10=30%
(2) First quarter pricing = a (1 + 25%) = 5 / 4A
Third quarter pricing = 5 / 4A × 90% = 9 / 8A
(1.5 + 1) B = 2.5B units sold in the third quarter
Total profit in the third quarter = 9 / 8A × 2.5b-2.5ab = 5 / 16ab
Total profit in the third quarter increased by (5 / 16ab-1 / 4AB) / (1 / 4AB) = (1 / 16) / (1 / 4) = 0.25 = 25% compared with the first quarter
For reference only
The resultant force of two different forces F1 and F2 acting on the same object is f
A. When F1 and F2 are doubled at the same time, f is increased by 4 times
B. F1 and F2 increased by 10N at the same time, and f also increased by 10N
C. When F1 increases by 10N, F2 decreases by 10N, and f remains unchanged
D. F1 and F2 are reduced by half at the same time, and F is also reduced by half
Choose D
The simple calculation process of 36 times 3 / 34,
36 times 3 / 34
=(34+2)*3/34
=34*3/34+2*3/34
=3+3/17
=3 and 3 / 17
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Find the rules 1, 4, 9, 18, 35,
I like doing this best
1 4 9 18 35 68
3 5 9 17 33
2 4 8 16
So it's 68
Do you understand
What is the product of multiplication of two prime numbers greater than 3
Prime numbers greater than 3 can be expressed as 6N + 1 or 6n-1
The product of multiplication of two prime numbers greater than 3 is also an odd composite number of the form 6K + 1 or 6k-1
Above n, K is an integer
Note:
(6a+1)*(6b+1)=...
(6a-1)*(6b-1)=...
(6a+1)*(6b-1)=...
C language expression for "x is greater than or equal to 10, y + Z is greater than or equal to 6"
C language expression for "x is greater than or equal to 10, y + Z is greater than or equal to 6"
x>=10,and y+z>=6
Find the law
③ 1 3 9 11 17 19 ④1 2 4 7 11 16 ⑤1 2 3 5 8 13
① In this question, 1 + 2 = 3 3 + 4 = 7 7 + 6 = 13 13 + 8 = 21 21 + 10 = 31 ② In this question, each number is twice the number before it. 2 * 2 = 4 * 2 = 8 * 2 = 16 * 2 = 32
Observe the following numbers: 1, 6, 11, 16, 21.1, write the expression of its nth number. 2, which of its terms is equal to 2006
1+5(N-1)
402 items
The formula of friction
The formula of sliding friction f = UN, where n is the pressure, and N = MGU is the sliding friction coefficient when it is on the horizontal ground, which is related to the material. Friction 1. Definition of friction (1): when two objects are in contact with each other, when they are about to move or have moved relative to each other, they will produce a force on the contact surface to hinder the relative movement, and this force will
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