So Volume of cylinder is pi*r^2*h = 1,000
Then lightest one means you have the smallest surface area. Which is one base and then the area of the surface. SA = pi*r^2 + 2pi*r*h
So now you have 2 equations, so:
h = 1,000/(pi*r^2)
So then SA = pi*r^2 + 2pi*r*(1,000/(pi*r^2) = pi*r^2 + 2,000/r
Derivative of SA is then 2pi*r -2,000/r^2. Set to 0
2pi*r-2,000/r^2 =0 --> 2pi*r^3 = 2,000 --> r^3 = 1,000/pi --> r = 10/pi^(1/3)
Now go back to the volume function: pi*r^2*h =1,000 --> 1,000/(pi*100/pi^(2/3)) = h
<span>h = 10 / pi^(1/3)</span>
Since the full price is $12 and the person paid one shirt full price and the other 50% off, the fraction would be 6/12. When you simplify that fraction you are left with 1/2. This means that the answer you are looking for is letter C.
Price of DVD player ≥ $150
Saved = $80
Amount needed = $150 - $80 = $70
Saving per week = $10
Let x be the number of weeks needed:
80 + 10x ≥ 150
10x ≥ 150 - 80
10x ≥ 70
x ≥ 70 ÷ 10
x ≥ 7
Answer: She needs to save for for at least 7 weeks.
Answer:
x=5
Step-by-step explanation: