Answer
The probabilities are:
tails $=\frac{1}{5}$,
heads $=\frac{4}{5}$
Work Step by Step
If $T$=tails and $H$=heads, then if $P(T)=x$, then $P(H)=4x.$
We know that $P(T)+P(H)=1$ so
$x+4x=1\\5x=1\\x=\frac{1}{5}.$
Therefore
$P(T)=x=\frac{1}{5}$, $P(H)=4x=\frac{4}{5}.$
