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The store bought 5 cases of apples and 8 cases of pears. Each box of apples weighed 8.8 kg. The weight of each box of pears was 2.5 times that of each box of apples. How many kilograms of pears did the store buy?
8.8×2.5×8，
=22×8，
=176 (kg);
A: the shop bought 176 kg more pears
Mother bought 3 kg of apples and pears and paid 69 yuan in total? equation
Let's say x yuan per kilogram of apples
3x10.8+3x=69
32.4+3x=69
3x=69-32.4
3x=36.6
x=36.6/3
x=12.2
A: apples are 12.2 yuan per kilogram
Mother bought the same weight of pear and apple, shared 150 yuan, known to buy 2 kg of Apple money and 3 kg of pear money is equal. How much did mother buy pear? What about apples? By 21:30
Suppose it costs X Yuan to buy an apple and a kilogram of apple,
Then:
2x/a=3(150-x)/a
obtain:
X = 90 yuan
The price of pear is 150-x = 60 yuan
Xinhua Bookstore sold two kinds of books in one day, with a total of 1560 yuan; for the development of agricultural science and technology, books of type B were sent to the countryside and sold for 1350 yuan. If the cost of a and B books were calculated respectively, a book could make a profit of 25% and B book would lose 10%. How much profit (or loss) would the bookstore make in this day
Suppose the cost of a kind of book is x yuan, B kind of book is y yuan
From the meaning of the title
x+25%x＝1560
y−10%y＝1350 ，
The solution
x＝1248
y＝1500 ．
Therefore, the profit (1560 + 1350) - (1248 + 1500) = 162 (yuan)
Answer: this bookshop this day total profit 162 yuan
Solution of one variable linear equation system! And two variable linear equation system solution!
Solution of one variable first order equation system: directly solve each equation. Solution of two variable first order equation system: replace y with X to form one variable first order equation, or change it into one variable first order equation by addition and subtraction elimination method
Please help us to solve two math problems (one or two or three must be used) 1. It is known that the sum of the numbers in the ten digits of a two digit number and the number in a single digit is 9. If a 0 is inserted between the bits and the tens, the three digits obtained are 6 times of the original two digits. How many are the original two digits 2. From the Summer Camp Camp to the school, go down the mountain first and then walk on the flat road. A young pioneer rode down the mountain at the speed of 12 km / h and 9 km / h through the level road. It took 55 minutes to get to the school. When he came back, the speed of crossing the level road was unchanged, but he went up the mountain at the speed of 6000 meters per hour. It took 1 hour and 10 minutes to return to the camp
1. The original two digit number x, the number of one digit YX + y = 9100x + y = 6 * (10x + y) = 60x + 6y40x = 5y8x = YX = 1y = 8, the original two digit number is 182
The solution of one variable linear equation,
a+bx=0
BX = - A
x=-a/b
Solution steps of one variable linear equation
Go to the denominator,
Remove brackets,
transposition,
Merge similar items;
The coefficient is reduced to 1
There are mainly steps in this direction, but these steps do not necessarily appear in specific equations
Solution of one variable linear equation (70-X)X=384
∵ (70-x) x = 384 = = > 70x-x? = 384 = = > x? - 70X = - 384 = = > x? - 70X + 35? = 35? - 384 = = > (x-35) mm2 = 841 = = > x-35 = ± 29 = = > x = 35 ± 29
Solving two variables and one equation
"Elimination" is the basic idea of solving the first-order equation of two variables. The so-called "elimination" is to reduce the number of unknowns, so that the multivariate equation is finally transformed into the equation of one unknown, and then solve the unknown number. This idea is called elimination of elements. For example, 5x + 6y = 7 2x + 3Y = 4, changed to 5x + 6y = 7 4x + 6y = 8
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