The base price of the iphone is $350 and additiobal charge of a month is $67. So additional charge for p months is $67p.
Determine the equation for total cost of iphone after p momths.
Reading that as

By the fundamental theorem of calculus, the first derivative is

and so the second derivative would be

which means
D. 2:3..
Ratios are basically fractions. Find a number that both numbers in the ration can divide into. In this case, it's 3. 18/3 is 6 and 27/3 is 9. but you're still not done, because 6/3 is 2 and 9/3 is 3
A. Because when you try to find something (per) you will divide
I hope this helps