giải toán bằng Tiếng Anh

N

nguoihocduoc2

english

Thirty-six dogs and chickens are cooped together.
There are one hundred legs altogether.
How many are there in each group?

dịch nghĩa:
Vừa gà, vừa chó
Ba mươi sáu con
Bó lại cho tròn
Chẵn một trăm chân.
Hỏi mấy gà, mấy chó?

giai:
Let x be the number of dogs, let y be the number of chickens.
We can set up equations as follow:
{x+y=36………………(1)
{4x+2y=100……….(2)
Multiply the bottom equation by 2. So we’ll have:
{2x + 2y = 72…………...(3)
{4x + 2y = 100…………..(4)
_____________________
=> 2x = 28
=>x = 14
=>y = 36 – 14 = 22
Answer: the number of dogs is 14 ; the number of chickens is 22
 
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