A(t)=A0*(1/2)^(t/30)
where t=elapsed years
A0=initial mass at t=0.
Below are the choices that can be found from other sources:
A) 36 pi
<span>B) 6 pi </span>
<span>C) 27 pi </span>
<span>D) 216 pi </span>
<span>E) 48 pi
</span>
A sphere's volume is (4/3)*pi*r^3.
<span>The diameter of the balloon is 6 inches. The diameter is twice the radius. The radius is 3 inches. </span>
<span>(4/3)*pi*3^3 = 36 * pi </span>
<span>But the balloon is only 3/4 full. So </span>
<span>36 * (3/4) * pi = 27 * pi. </span>
<span>The balloon has 27 pi cubic inches of water.</span>
Remark
You have given the second best answer. Your answer is |x|<1. You should have open circles at 1 and - 1.
Solution
I have enclosed a graph that is not a number line. You could confine yourself to a number line just by tracing out the blue solution (which is the answer you want)
The red solution is what you did.
The blue solution does not include x = 1 nor does it include x = - 1. The number line would show 1 < x < ∞ and -∞ < x < -1