9514 1404 393
Answer:
the marked choice is the correct one
Step-by-step explanation:
A suitable calculator or web app can reduce this matrix for you.
The solution is represented by the matrix ...
![\left[\begin{array}{ccc|c}1&0&0&1\\0&1&0&-1\\0&0&1&3\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Cc%7D1%260%260%261%5C%5C0%261%260%26-1%5C%5C0%260%261%263%5Cend%7Barray%7D%5Cright%5D)
An hour is 60 mins long. 15 mins is 1/4 of that. So 60/4=15. And since he’s running at 12 miles per hour, then 12/4=3. Which means he will travel exactly 3 miles in 15 minutes.