#### Answer

$d=20$ miles

#### Work Step by Step

RECALL:
For situations involving time (t) , distance (d) and rate (r, sometimes referred to as speed), the formula for distance is:
$d=rt$
The given situation has:
$r=80$ mph
$t =15$ minutes = $\dfrac{1}{4}$ hour
Use the formula above to obtain:
$d=rt
\\d=80(\frac{1}{4})$
$\\d=20$ miles