OG详解-OG8 数学2 Q4

Choice C is correct. It’s given that the cost of renting a tent is $11 per day for d days. Multiplying the rental cost by the number of days yields $11d, which represents the cost of renting the tent for d days before the insurance is added. Adding the onetime insurance fee of $10 to the rental cost of $11d gives the total cost c, in dollars, which can be represented by the equation c = 11d+10.
Choice A is incorrect. This equation represents the total cost to rent the tent if the insurance fee was charged everyday. Choice B is incorrect. This equation represents the total cost to rent the tent if the daily fee was $(d +11) for 10 days.  Choice D is incorrect. This equation represents the total cost to rent the tent if the daily fee was $10 and the onetime fee was $11.