The number of miles for which Tonya and Beth would charge the same amount is 9 miles.
Step-by-step explanation:
Tonya's dog-walking service:
Flat rate per month = $18
charges per mile = $2
Let the number of miles = m
Total charge ($) = 2m + 18
Beth dog-walking service:
Flat rate per month = $0
charges per mile = $4
Let the number of miles = m
Total charge ($) = 4m + 0 = 4m
To determine the number of miles for which Tonya and Beth
would charge the same amount, we will equate both charges together:
2m + 18 = 4m
Collect like terms:
18 = 4m - 2m
18 = 2m
Divide through by 2
18/2 = m
m = 9
Therefore, the number of miles for which Tonya and Beth would charge the same amount is 9 miles.