Data Sufficiency

If each customer at the outdoor movie last night came in a car, what was the number of cars in which the customers came to the outdoor movie last night?

1. The average (A.M) number of customers per car coming to the outdoor movie last night was 2.
2. Total receipts at the outdoor movie last night were $4,500 at $5 per customer .

[spoiler]OA: C. I have a doubt here: From 2, we can find that total number of customers were 900. Combining 1 and 2 how do we know the actual number of cars, since the statement 1 only states the average number of customers per car not the actual number of customers per car. [/spoiler]

Avg customers per car (from statement 1 ) = 2
Total customers ( from statement 2 ) = 900

As
Total # of cars * avg customers per car = total customers

so
Total # of cars = total customers / avg customers per car

Total # of cars = 900/2 = 450

From 2, No.of customers = 900
From 1, Avg.No of customers per car =2

So, No. of cars = 900/2 = 450

Hence C