The answer is B, hope this helps
Answer:
B
Step-by-step explanation:
Let x = every day he rented the kayak
Since the store charges $60 for each day, multiply x by 60 like this: 60x
They also have $25 on top of that; 60x + 25
This all has to equal $325; 60x + 25 = 325
To solve for x, subtract 25 from both sides
60x + 25 = 325
- 25 - 25
60x = 300
Divide both sides by 60
60x/60 = 300/60
x = 5
This means Tobias rented the kayak for 5 days

Above, I changed the fraction form of x and y into exponential form so it is easier to see the differentiation. Now, we can differentiate:

Now that we have dy/dx, we can plug in the x, which is 4, and the y, which is 4/19. We know these values of x and y because your question stated y(4) = 4/19.
So first you figure out what 25% of $40.00 is whitch would be $30.00. Then what i think you would do next is add 6% of the cost of the dress. 6% of $30.00 is $1.80. so $30.00 + $1.80 = $31.80 dollors for the dress.