The amount of the radioactive material in the vault after 140 years is 210 pounds
<h3>How to determine the amount</h3>
We have that the function is given as a model;
f(x) = 300(0.5)x/100
Where
- x = number of years of the vault = 140 years
- f(x) is the amount in pounds
Let's substitute the value of 'x' in the model
f(x) = 300(0.5)x/100


f(140) = 210 pounds
This mean that the function of 149 years would give an amount of 210 pounds rounded up to the nearest whole number.
Thus, the amount of the radioactive material in the vault after 140 years is 210 pounds
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Step-by-step explanation:
3800 is the general amount, but before he can touch it, 800 and 200 are taken away from it for the described purposes.
so, what is left is
3800 - 800 - 200 = 2800
this is then the real amount he can do something with.
We know that 172 of them were wood, so the rest are metal. To find that number we do:
276 - 172 = 104 metal pins.
To find the percentage that they were metal, take the number of metal pins and divide by the total number of pins:
104/276 is about 0.3768.
Multiply this by 100:
37.68
So, the percent of metal pins is 37.68%.
That is false. The parabola opens to the right.