#### Answer

The number of 20th century deaths with war, famine, and tobacco is $124,111,\text{ and }71\text{ million}.$

#### Work Step by Step

Let us consider that the number of deaths in the 20th century due to war, famine, and tobacco is x, y, and z millions respectively. The number of deaths combing war, famine, and tobacco is 306 million; therefore the equation becomes:
$ x+y+z=306$
The difference between the number of deaths between war and famine is 13 million; thus we get:
$ x-y=13$
The difference between the number of deaths between war and tobacco is 53 million; therefore, we get:
$ x-z=53$
From the equation $ x-y=13$,
$ y=x-13$
From the equation $ x-z=53$,
$ z=x-53$
Put the value of y and z in equation $ x+y+z=306$ as given below:
$\begin{align}
& x+\left( x-13 \right)+\left( x-53 \right)=306 \\
& 3x-66=306 \\
& 3x=372 \\
& x=124
\end{align}$
From $ y=x-13$,
$\begin{align}
& y=124-13 \\
& =111
\end{align}$
From the equation $ z=x-53$
$\begin{align}
& z=124-53 \\
& =71
\end{align}$
Hence, the number of deaths in the 20th century due to war, famine, and tobacco is $ x=124,y=111,z=71$ million respectively.