I'm tentatively changing my answer to say this kind of relies on practical knowledge of how stores tend to operate. If 20 coupons are given out, the store has sold all 500 shirts, arguably at a loss to the retailer. They have to have more shirts in stock to be sold at full price because, well, that's how they make money. It's more likely that such a store would carry more than just 500 shirts at the start of each day, so A is (probably) wrong.
Just asking, what book is it?
There are no graphs available.
Answer:
101.07ft^2
Step-by-step explanation:
Given data
radius= 5ft
h= 9ft
When the radius and height are both multiplied by 1/2
radius= 5/2ft = 2.5ft
height= 9/2 ft= 4.5ft
The expression for the surface area of the cone is
A=πr(r+√h^2+r^2)
Substiute
A= 3.142*2.5(2.5√4.5^2+2.5^2)
A= 7.855(2.5√20.25+6.25)
A= 7.855(2.5√26.5)
A= 7.855(2.5*5.147)
A=101.07 ft^2
Hence the surface area is 101.07ft^2
Answer:
the question is incomplete, so I looked for a similar one:
<em>After the release of radioactive material into the atmosphere from a nuclear power plant, the hay was contaminated by iodine 131 ( half-life, 8 days). If it is all right to feed the hay to cows when 10% of the iodine 131 remains, how long did the farmers need to wait to use this hay? </em>
iodine's half life (we are given x, we need to find b):
0.5A₀ = A₀eᵇˣ
x = 8 days
we eliminate A₀ from both sides
0.5 = eᵇ⁸
ln 0.5 = ln eᵇ⁸
-0.69315 = b8
b = -0.69315 / 8 = -0.08664
since the farmers need to wait until only 10% of the iodine remains (we already calculated b, now we need to find x):
0.1A₀ = A₀eᵇˣ
0.1 = eᵇˣ
ln 0.1 = bx
where b = -0.08664
x = ln 0.1 / -0.08664 = -2.302585 / -0.08664 = 26.58 days
