To find the unit rate for inches per mile on the map, we need to first convert the length of Road A from miles to inches.
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Convert miles to inches for Road A:
- There are 63,360 inches in a mile.
- Road A is \( 1 \frac{1}{4} \) miles long.
To convert \( 1 \frac{1}{4} \) miles to an improper fraction: \[ 1 \frac{1}{4} = \frac{5}{4} \text{ miles} \]
Now convert to inches: \[ \frac{5}{4} \text{ miles} \times 63,360 \text{ inches/mile} = \frac{5 \times 63,360}{4} = \frac{316,800}{4} = 79,200 \text{ inches} \]
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Find the unit rate for inches per mile:
- Length of Road A on the map: \( 1 \frac{7}{8} \) inches.
- Convert \( 1 \frac{7}{8} \) inches to an improper fraction: \[ 1 \frac{7}{8} = \frac{15}{8} \text{ inches} \]
Now, the unit rate can be calculated as: \[ \text{Unit rate (inches per mile)} = \frac{\text{Length on the map (inches)}}{\text{Actual length (miles)}} \] \[ \text{Unit rate} = \frac{\frac{15}{8}}{\frac{5}{4}} = \frac{15}{8} \times \frac{4}{5} = \frac{15 \times 4}{8 \times 5} = \frac{60}{40} = \frac{3}{2} \]
Thus, the unit rate is: \[ \frac{3}{2} \text{ inches per mile} \]
- Calculate the length of Road B on the map:
- Length of Road B: 6 miles.
- Using the unit rate of \( \frac{3}{2} \) inches per mile, we can find the length on the map: \[ \text{Length on the map} = 6 \text{ miles} \times \frac{3}{2} \text{ inches/mile} = 6 \times \frac{3}{2} = 9 \text{ inches} \]
Final Answers:
- Unit rate: \( \frac{3}{2} \) inches per mile
- Length of Road B on the map: 9 inches