Question

At Go-Cart World, each go-cart costs $4. For a birthday party, a group of 7 friends are allowed to take 1 go-cart. The total cost is the function of the number of rides. What is the domain & range?

Answer 1

range has to be a multiple of 4 i.e {0,4,8,....}
domain can be any positive integer i.e. {0,1,2,...}

Needs review

Answer 2

The total cost is function of the number of rides.
Let x be the number of rides.
So the total cost would be:
\[f(x) = 4 x\]
where 4 is the cost of each go-cart and x is the number of rides.

x represent the number of rides (or rounds), so x can be any natural
\[x \in IN \implies Domain = IN\]

The range is just which values f can assume. Since x can be anything non-negative, f can be (4 times a natural number): 0, 4, 8, ...

So, \[Range = \{0, 4, 8, ...\}\]