The answer is the last one 7/8 x -3/4 =6
Time Distance Distance / Time
2hrs 90 miles 90 miles / 2 hrs = 45 miles / hr
3hrs 135 miles 135 miles / 3 hrs = 45 miles / hr
5hrs 225 miles 225 miles / 5 hrs = 45 miles / hr
6hrs 270 miles 270 miles / 6 hrs = 45 miles / hr
Constant of proportionality is 45 miles / hr. This is the same for the four values. The unit rate is also 45 miles / hr.
Let us assume the Distance , d is directly proportional to Time, t
d α t
d = kt
Constant of proportionality is k which is D/T
d = 45t
$1.32 per bottle because you would divide $5.28 into 4 and get $1.32