Answer
$P(T)=\dfrac{1}{3}$, and $P(H)=\dfrac{2}{3}.$
Work Step by Step
If $T$:tails, $H$: heads, then if $P(T)=x$, then $P(H)=2x.$
We know that
$P(T)+P(H)=1\\x+2x=1\\3x=0\\x=\dfrac{1}{3}$.
Thus
$P(T)=\dfrac{1}{3}$, and $P(H)=\dfrac{2}{3}.$
