数学好英语又好的进来看看呀!

来源：百度知道 编辑：UC知道 时间：2024/05/29 00:13:55
帮我把下面的题解一下~~谢谢了~~
A physical fitness enthusiast decides to devote her exercise time to a combination of
jogging and cycling. She wants to earn “aerobic points” (a measure of the benefit of
the exercise to strengthening the heart and lungs). She jogs at 6 kilometers per hour
and cycles at 18 kilometers per hour. An hour of jogging earns 12 aerobic points, and
an hour of cycling earns 9 aerobic points. Each week she would like to earn at least 36
aerobic points, cover at least 54 kilometers, and cycle at least as much as she jogs. How
many hours of each activity should she do each week to meet the above requirements,
but minimize the total time spent working out?

SOLUTION：
to suppose:
X is her jogging time each activity
Y is her cycling time each activity
Then
6*7*X+18*7*Y=54
12*7*X+9*7*Y=36
==> X=4/21(hour),Y=23/63(hour)
answer1:4/21+23/63 (hour)=0.7(hour)
answer2:7*(4/21+23/63 )=4.9(hour)

首先我给你翻译一下这道题目的意思：
一项体能爱好者决定将她的运动时间，以结合
慢跑和骑自行车。她要赚"有氧点" （用以量度造福
实兵演练，加强心脏和肺） 。她jogs在六公里每小时
和周期在18公里的时速。一个小时的慢跑赚12个好氧点，并
一个小时的自行车赚九有氧点。每星期她想赚取至少36
有氧点，涵盖了至少有54公里，周期至少能像她想得那样。如何
多个小时的每项活动都应这样做，她每个星期要符合上述要求，
但尽量减少总实际工作时间呢？
解法上楼有了 我给你翻译一下吧：
解决方案：
假设：
X是她的跑步时间，每项活动
Y是，她骑自行车时间，每项活动
然后
6 * 7 * x +18 * 7 *为Y = 54
12 * 7 * x +9 * 7 *为Y = 36
== > x = 4 / 21 （小时） ，为Y = 63分之23 （小时）
answer1 ： 4 / 21 +23 / 63 （小时） = 0.7 （小时）
answer2 ： 7 * （ 4 / 21 +23 / 63 ） = 4.9 （小时）

6 * 7 * x +18 * 7 *为Y = 54
12 * 7 * x +9 * 7 *为Y = 36
== > x = 4 / 21 （小时） ，为Y = 63分之23 （小时）
answer1 ： 4 /