9.9=9×9=81 and you have to multiply
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
Learn more amount radioactive decay here:
brainly.com/question/11117468
#SPJ1
It is asking you to slice off 40% of the bounce height in each subsequent bounce.
So you start with full height 1, that's n = 0 bounces. Then after n = 1 bounce the new height is .6. After the second bounce, n = 2, the height becomes .6 X .6 = .36. And after n = 3, we have .6 X .6 X .6 = .216
So by induction we see that h(n = 5) = .6^n = .6^5 = 0.07776 = .078 of its original height or H = .078*200 = 15.6 ft. after five bounces. ANS. 16.0 if rounded to the nearest tenth
:)