Answer:

Step-by-step explanation:
step 1
Find the area of complete circle
The area of the circle is given by the formula

we have

substitute


step 2
Find the area of the shaded region
we know that
The area of complete circle subtends a central angle of 360 degrees
so
using proportion
Find out the area of the shaded region if the central angle is equal to 80 degrees

Add all of the percents up and then divide by 3. You get 89.6%
It looks like you're given

Then by the additivity of definite integrals this is the same as

(presumably this is what the hint suggests to use)
Then by the fundamental theorem of calculus, we have

Revenue > Cost
R(x) > C(x)
0.50x > 10+0.20x
0.50x-0.20x > 10
0.30x > 10
x > 10/0.30
x > 33.333 which is approximate
Round up to the nearest whole number to get x = 34. You need to sell at least 34 cups of lemonade to have the revenue R(x) be larger than the cost C(x)
Answer: 34
The answer is the first answer choice