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?