Answer:
Let's assume Karl rents the bike for x hours. Then the cost of renting the bike can be expressed as:
Cost = 7x + 9.5
We know that the maximum cost Karl can afford is $55. So we can set up an equation:
7x + 9.5 ≤ 55
Subtracting 9.5 from both sides:
7x ≤ 45.5
Dividing both sides by 7:
x ≤ 6.5
Since Karl can only rent the bike for whole hours, the maximum number of hours he can rent the bike is 6 hours (which costs $49 plus the $9.5 flat fee, for a total of $58.5). If he rented it for 7 hours, it would cost $60.5, which is over his budget.