Answer:
w+2r>12
w+2r<20
Step-by-step explanation:
Walking :
Speed = 3 mph
Time of walking = w hrs (given)
Total distance covered = Speed x time
D1=3w
Running
Speed=6 mph
Time of running = r hrs ( Given)
Total distance covered = Speed x time
D2 = 6r
The condition says that
Total distance > 36 miles
That is
D1+D2>36
3w+6r>36
Dividing both sides by 3 we get
w+2r>12
Also
D1+D2<60
3w+6r<60
w+2r<20
Hence the system of inequations representing the above condition are
w+2r>12
w+2r<20