25% is equal to
. To get 25% of 300, we multiply 300 by either 0.25 or
. This gives us
(x-30)+(x+76)=180
x-30+x+76=180
2x+46=180
2x=134
x=67
67-30=37
67+76=143
<1=37, <2=143
Answer:
16.07 milligrams
Step-by-step explanation:
From the question,
Using the formula of radioactive decay,
R/R' = 2ᵃ/ᵇ..................... Equation 1
Where R = Original mass of the polonium-210, R' = Final mass of polonium-210 after decaying, a = Total disintegration time, b = half life of polonium-210.
Make R' the subject of the equation
R' = R/(2ᵃ/ᵇ)................ Equation 2
Given: R = 100 milligrams, a = 1 years = 365 days, b = 138.39 days
Substitute these values into equation 2
R' = 100/(2³⁶⁵⁰⁰/¹³⁸³⁹)
R' = 100/(6.222)
R' = 16.07 milligrams of plonium-210
Answer:
2.73
Step-by-step explanation:
You round 6 up to get 2.73
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