Anthony rented a car for $37 a day for 7 days. There is also a charge of 45 cents for every mile driven over an average of 100 miles per day of rental, and a collision waiver of $9 per day. Anthony drove 825 miles in 7 days. Gasoline costs were $49, parking and tolls were $32. What was the cost per mile for the 7 days?

So you need to add up all the costs and divide by the total mileage for the trip.

We don't usually give actual answers here, but we help you find them.
You could draw a chart:
First how about 7 columns for each day, with an 8th column for totals
Then rows for $$$
Put 37 across the 7 days, right? And then 9? Those were flat charges each day.
Now the gas and tolls.. flat charges for the whole trip, can go in the totals column
Last, the mieage.
How will you calculate that? 100 miles per day are free, so how many will you multiply times 45 cents?

I'm not going to do the math for you, but will gladly tell you how to get the answer. Sounds like a homework assignment I would have given way back when I taught middle school/high school math.
1. Figure out how much you have to pay for just renting the car for seven days, by multiplying the daily cost(How much each day? For 7 days? That's easy.) Now, write that answer down.
2. Figure out how many miles over 100 miles for seven days you actually drove. (Hmn, not hard either. 7 days at a 100 miles per day is 700, isn't it? Now, do a simple subtraction.)
3. Take that answer and multiply it by the amount you said you had to pay extra if you went over 100 mile per day on average -. (Your answer to number 2) Write this answer down under your answer to number 1.
4. If you spent a total of $49 for gas you must be driving a very efficient car! But, if that is the total you spent for gas, write it down under the answer to #3, and also write the $9 extra charge.
5. Now, just write down the amount for tolls in the same column and add these four number.
6. Here's the hardest arithmetic in the problem - division! But it is easy to remember how to do this. I told my students - and tell myself every time I have a similar problem - "Money on top." So, your answer to number 5 is "on top" of a fraction you make with it and the only other available number, the number of miles you drove. That means you divide $$$ by the total miles Anthony drove.
You can use this method for all similar problems! Remember "Money on top." Put it in the calculator first if you're doing division.

720 mm - 48 cm