[计量] 一题数学题求解

楼主: brendenPTT (欧美)   2019-05-10 21:42:49
The width and the length of a rectangular piece of plywood are 4 feet and 8 feet, respectively. Along one edge of the plywood, a strip x inches wide and 8 feet longis removed. Then, along an edge perpendicular to the 8-foot edge, a strip x inches wide is removed. For what value of x will the remaining rectangular piece have width and length in the ratio of 2 to 5? ( 1 foot = 12 inches)
我知道这题要求的是
可以让宽度/长度会等于2/5的x值,
但是卡在这句
Then, along an edge perpendicular to the 8-foot edge, a strip x inches wide is removed.
我的解读是:
在垂直于另一个8-foot的边上,再移除x inches
这样不就代表
再把另一个4 feet的宽(垂直于8-foot)
移除掉x inches吗?
式子写成
4-x /8 =2/5 求得x=9.6
但答案是16
是用 4-x/8-x = 2/5 求得的
不太懂为什么要把8减掉x
不是应该要用垂直于8-foot 的边(4feet) 去减x吗?
描述的有点复杂,还烦请版上的大大
帮小弟我解答一下,看是我哪里理解错了
感谢再感谢!

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