What is the base representation of the number 219

Iam so stuck. what is the worked out answer for this question?

Alength on a map is 7.5 inches. thescale is 1 inch: 5 miles. what is theactual distance? a 1.5 miles c 12.5 milesb 2.5 miles d 37.5 miles

5× 1/2 = ? a) more than 5 because you are multiplying by a whole number b) 5/10 because you multiply the numerator and denominator by 5 c) less than 5 because you are multiplying by a number that is more than 1 d) less than 5 because you are multiplying by a number that is less than 1