Answer:
Price of Caleb's groceries before tax = $64
Step-by-step explanation:
Let the price of groceries before tax be =$ 
Sales tax charged = $1.60
Sales tax rate =2.5%
Sales tax charged in terms of
will be = 2.5% of the Original price of grocery =
So, we have,

Dividing both sides by 

∴ 
∴ Price of Caleb's groceries before tax = $64
390.20 is the answer because 4%of 2880 is 115.20 plus 275.00 is 390.20
Answer: -216
Step-by-step explanation:
To solve the exercise you must use the formula shown below:

Where:

You should find 
The formula to find it is:

Where d is the difference between two consecutive terms.

Then:

Substitute it into the first formula. Therefore, you obtain:

First, this shoudnt be in mathematics and second, i think this is socila studies.