#### Answer

Across the $40~\Omega$ resistor, the potential difference is $20~V$
Across the $60~\Omega$ resistor, the potential difference is $30~V$

#### Work Step by Step

We can find the equivalent resistance of the two resistors in series:
$R = 40~\Omega + 60~\Omega = 100~\Omega$
We can find the current in the circuit:
$I = \frac{V}{R} = \frac{50~V}{100~\Omega} = 0.50~A$
We can find the potential difference across the $40~\Omega$ resistor:
$\Delta V = I~R = (0.50~A)(40~\Omega) = 20~V$
We can find the potential difference across the $60~\Omega$ resistor:
$\Delta V = I~R = (0.50~A)(60~\Omega) = 30~V$