To determine how far Martina can walk in one hour based on the information given, we need to find her walking rate in miles per hour and then use that rate to calculate the distance she can travel in one hour.
1. Distance Walked: Understand that Martina walked [tex]\(\frac{3}{4}\)[/tex] of a mile.
2. Time Taken: The time taken for this walk is [tex]\(\frac{1}{5}\)[/tex] of an hour.
3. Calculate Walking Rate: The walking rate, or speed, can be calculated by dividing the distance by the time taken. Thus, we have:
[tex]\[
\text{Rate (miles per hour)} = \frac{\text{Distance}}{\text{Time}} = \frac{\frac{3}{4}}{\frac{1}{5}}
\][/tex]
4. Simplify the Rate Calculation:
[tex]\[
\frac{\frac{3}{4}}{\frac{1}{5}} = \frac{3}{4} \times \frac{5}{1} = \frac{3 \times 5}{4 \times 1} = \frac{15}{4} = 3.75
\][/tex]
So, Martina's walking rate is 3.75 miles per hour.
5. Distance in One Hour: Now, we need to determine how far Martina can walk in one hour at this rate. Since her walking rate is 3.75 miles per hour, in one hour, she would walk 3.75 miles.
Therefore, the distance Martina can walk in one hour is:
[tex]\[
\boxed{3 \frac{3}{4} \text{ miles}}
\][/tex]
Thus, the correct answer is:
[tex]\[
\text{B. } 3 \frac{3}{4} \text{ miles}
\][/tex]