Terry opened a savings account in december with $132 and saved $27 each month beginning in january the value of terrys account in july, then calculate the amount and evaluate the reasonableness of your estimate

Let S be the amount in a savings account. 
Let m be the number of months.

General equation
S = 132 + 27m

Specific question
July is the 7th month of the year including both January and July.
S = 132 + 7*27
S = 132 + 189
S = 321

Reasonableness?
Good question. You could estimate an answer.
Start with 150 dollars and say that you add 25 a month.
7 * 25 = 175
S = 150 + 175 = 325 All of this was done in my head. Since the exact answer obtained using the formula is 321, I think that's pretty reasonable using my estimate is a guide.

we know that

zeros of any function f(x) are values of x where f(x)=0

Here , f(x) is profit function

so, f(x)=0 when x=15 and x=70

f(x)=0 means profit is 0

and profit is zero means neither gain nor loss

so, woodworker won't either loss or gain when x=15 and x=70

so, option-BAnswer