To find out how many miles apart the towns are, we first need to convert the measurement from inches to miles using the scale given on the map.
1 inch represents 20 miles. The distance measured between the towns is 2 and 5/8 inches.
First, we convert 2 and 5/8 inches to an improper fraction: \[ 2 \frac{5}{8} = \frac{2 \times 8 + 5}{8} = \frac{16 + 5}{8} = \frac{21}{8} \]
Next, we multiply this distance by the scale of miles per inch: \[ \text{Distance in miles} = \left(\frac{21}{8} \text{ inches}\right) \times 20 \text{ miles/inch} \]
Calculating this: \[ \text{Distance in miles} = \frac{21 \times 20}{8} = \frac{420}{8} = 52.5 \text{ miles} \]
52.5 miles can also be expressed as \( 52 \frac{1}{2} \) miles.
Hence, the towns are 52 and one-half miles apart.
The correct answer is D. 52 and one-half miles.