Answer
$y=2*x+2.50$
Work Step by Step
If the taxi driver charges 40 cents for each $1/5$ mile, we can multiply by 5 to get 200 cents or 2 dollars. This is the amount he charges per mile in addition to the $2.50$
Mapping this with $y=mx+b$ where y is cost, x is miles, m is rate, and b is initial cost,
$y=2*x+2.50$
