Answer:
$36
Explanation:
The store rents Bicycle and Helmet.
For every 1 hour, a customer pays the following:
Bicycle: 
$8 for every ONE HOUR
For THREE HOURS, the cost would be: 
$8 * 3hours = $24
(The store rents the BICYCLE at $24 for every three hours.)
Helmet:
$4 for every ONE HOUR
For THREE HOURS, the cost would be: 
$4 * 3hours = $12
(The store rents the HELMET at $12 for every three hours.)
COST FOR BOTH BICYCLE and HELMET for three hours 
= $24 + $12 
= $36