Answer:
a) Destiny can run 1 mile is 6 minutes.
b) Destiny can walk back 1 mile is 16 minutes.
Explanation:
The running rate of Destiny is

So, she runs 1 mile in
= 6 minutes
Hence, Destiny can run 1 mile is 6 minutes.
The walking rate of Destiny is

So, she walks 1 mile in
= 16 minutes
Hence, Destiny can walk back 1 mile is 16 minutes.