Thomas rented 2 bicycles, which were late for return by 6 days. His fine for being late was 18$. If the fine for being late is count by multiplying the number of bicycles with the duration of the late, the answer would be:
fine = number of bicycle * duration of late
$18 =fine rate* 2 bicyles * 6 days
fine rate= (($18/ 2 bicyles) / 6 days) = $0.66 /bicycle days
