Total distance covered = 3 miles.
First part walked at the rate 4 miles per hour.
Let us assume x hours was walked in first part.
<em><u>Total distance covered in x hours at the rate 4 miles per hour = 4x.</u></em>
Second walk rate with meet with friend = 5 miles per hour.
Total time taken = 0.7 hours.
Therefore, time taken in second walk only = (0.7 - x) hours.
<u><em>Distance covered in second walk = 5 (0.7 - x).</em></u>
Total distance covered = distance covered in first part + distance covered in second part.
4x + 5 (0.7 - x) = 3 miles.
<h3>Therefore, correct option is 4x + 5(0.7 – x) = 3.</h3>