Please help me find the formula for b). I have tried everything already and it is driving me nuts trying to find a formula for this problem.

So far I have this f(x) = { 1 x > 1
{1 + x

f(x) = { 1 x > 1
{(10)(x) + x

I understand that the problem is asking for the formula but what I don't get is how to write a formula for it. Every problem is different so how as I suppose to write a general formula for it. Such as if the difference is .99 the maximum the customer would get back is 5 dollars + .99. So that wouldn't be the same for if the difference was .10. Please help me with this.

Thanks.

2. I am going to assume that the rules for the refund are this -- for an over-charge of $x: 1. Customer gets a min of$1 + x
2. If the overage is between $0.10 and$0.50, the customer gets a rebate of 10 times the overage plus the overage, for a total of 11 times x.
3. If the overage is $0.50 or more, then the custmer gets$5 plus x.

If this is correct, then you have:

$
y = \left \{\begin{matrix} {\1+x} & {for\ \0.00 \leq x \leq \0.10}\\{11x}&{for \ \0.10 \leq x \leq \0.50}\\{\5 + x}&{for \ \0.50 \leq x}\end{matrix} \right.
$