數學問題 5分
2007-08-09 4:19 am
A cat and a dog are not satisfied with their weights. If the weight of the cat is increased by 20% while that of the dog is decrease by 10%, their weights well be the same. What percentages of dog's orginal weight is cat's original weight?
回答 (2)
2007-08-09 4:45 am
✔ 最佳答案
Let the weights of the cat and the dog be w1 and w2 respectively. Thenw1 * (1 + 20%) = w2 * (1 - 10%)
w1 * 1.2 = w2 * 0.9
w1 = w2 * 0.9 / 1.2 = w2 * 0.75 = w2 * 75%
So, 75% of the dog's original weight is the cat's original weight.
2007-08-09 4:59 am
cat's orginal weight is x
dog's orginal weight is y
x*(1+20%)=y*(1-10%)
x=y*3/4
x=y*75%
so 75% of dog's orginal weight is cat's orginal weight
dog's orginal weight is y
x*(1+20%)=y*(1-10%)
x=y*3/4
x=y*75%
so 75% of dog's orginal weight is cat's orginal weight
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