Its D 15+15+15= 45 so there for it will be 45
5.34x10⁶ :) you're welcome!!!
60.
let x be the number you're trying to solve.
(x/100)25 = 15
x/4 = 15
x = 15(4)
x = 60
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
Answer:
78.5 m²
Step-by-step explanation:
The formula to find the area of a quarter of a circle: 
, where 
is the radius (diameter ÷ 2) and the 
is alterable.
1) Substitute the given values into the formula.
= 
2) Solve it.
= 
= 78.5
3) Round it off to the nearest tenth. In this case, it has already been rounded off.
