Answer:
1) 25+7(n-1)
When the above 'n'(hours) is substituted on the equation, it equals up to the right cost.
2) Given that n represents the no.of bikes, you just plug it in to the equation below.
250+39(n-1)
= 250+39(20-1)
= 250+39*19
= 250+741
= 991
