Hello!, this is a linear problem. So we can use y = mx + b
m = slope = rate = 2.10
b = initial cost = 5.00
y = total cost = 49.10
x = distance
Now, just plugin our information into our formula/model
y = mx + b
49.10 = 2.10x + 5.00
Now solve for x to find the distance
49.10 = 2.10x + 5.00
(-5.00) + 49.10 = 2.10x + 5.00 + (-5.00)
(-5.00) + 49.10 = 2.10x + 5.00 + (-5.00)
44.10 = 2.10x
44.10 / 2.10 = 2.10x / 2.10
44.10 / 2.10 = x
21 =x
x = 21
x = distance = 21
