Xiaohong used 27.2 yuan to buy 5 kg of apples and 4 kg of oranges. As a result, he turned the number of buying upside down, so that the remaining 0.4 yuan, so how much is the oranges per kilogram?
Xiaohong used 27.2 yuan to buy 5 kg of apples and 4 kg of oranges. As a result, he turned the number of buying upside down, so that the remaining 0.4 yuan, so how much is the oranges per kilogram?
2.8 yuan per kilogram of oranges.
Prosty, apples 4 kg and 5 kg of oranges. Therefore, it turned out to be 1 kg more apple and 1 kg of oranges less than the upside -down.
Colid oranges per kilogram of x yuan, then apples per kilogram (0.4 x) yuan per kilogram.
5 (0.4 x) 4x = 27.2.
This -solving equations, obtained: x = 2.8.
2.8 yuan per kilogram of oranges.
The application questions for the solution of the equations:
1, practical questions (review questions, clarify all known and end -knowledge conditions and quantitative relationships).
2, setting the end of the last (generally set, there is time to set the time), and the algebra of the final knowledge of the setting indicates all the final knowledge.
3, find an equivalent relationship column equation.
4, solving the equations, and find other finals.
5, test (test whether it is the solution of the original equation and whether it meets practical significance).
6, answer.
5 kg apple 4 kg orange = 27.2 yuan
4 kg apple 5 kg orange = 27.2-0.4 = 26.8 yuan
9 kg apple 9 kg orange = 27.2 26.8 = 54 yuan n1 kg apple apples 1 kg orange = 54/9 = 6 yuan
4 kg apple 4 kg orange = 6*4 = 24 yuan
1 kg apple = 27.2-24 = 3.2 yuan
1 kg orange = (27.2 (27.2 -3.2*5) /4=2.8 yuan
If the formula group, the solution is as follows
The apple unit price is x, and the unit price of oranges is y. 27.2; 4X 5Y = 26.8; from this to get x = 3.2; y = 2.8 is the unit price of orange 2.8 yuan/kg
27.2-0.4 = 26.8 (dollars)
(26.8 27.2) ÷ (5 4) = 6 (dollar)
Apple: 27.2-6x4 = 3.2 (yuan)
Orange: (27.2 -3.2x5) ÷ 4 = 2.8 (dollars)
Answer: Orange 2.8 yuan per kilogram.
Let apples per kilogram = x yuan per kilogram, orange per kilogram = y yuan
5x 4y = 27.2 → x = 5.44-0.8y-(1)
4x 5Y = 27.2-0.4 = 26.8-(2)
is replaced by (1) (2)
4*(5.44-0.8y) 5y = 26.8
21.76-3.2y 5Y = 26.8
1.8y = 5.04,, Y = 2.8, then x = 3.2
Therefore, oranges per kilogram of oranges are 2.8 yuan
27.2 26.8 = 54 (dollars)
54 ÷ 9 = 6 (yuan)
6 × 5 = 30 (yuan)
30-27.2 = 2.8 (yuan)