Given: Isotope $"x"$ is used as a radiotherapy source for treating cancer patient tumors. The plot below gives the fraction of isotope $"x"$ remaining versus time in hours.

$2$a$.$ What is the half life $T_{\frac{1}{2}}$ if isotope $"x"$ determined using the plot. State units.

$2$b$.$ What is the probability $($at any time $t)$ that isotope $"x"$ will decay?