Answer
Partial Pressure of $He$: $0.066\text{ atm}$
Partial Pressure of $Ne$: $0.100\text{ atm}$
Partial Pressure of $Ar$: $0.118\text{ atm}$
Work Step by Step
Partial Pressure of $He$
$200.\text{ torr}*\frac{1 \text{ atm}}{760 \text{ torr}}=0.263\text{ atm}$
We must multiply the pressure of $He$ by $\frac{1}{4}$ to account for the change from 1 L to 4L.
$0.263\text{ atm}*\frac{1}{4}=0.066\text{ atm}$
Partial Pressure of $Ne$
We must multiply the pressure of $Ne$ by $\frac{1}{4}$ to account for the change from 1 L to 4L.
$0.400\text{ atm}*\frac{1}{4}=0.100\text{ atm}$
Partial Pressure of $Ar$
$24.0\text{ kPa}*\frac{1\text{ atm}}{101.325\text{ kPa}}=0.237\text{ atm}$
We must multiply the pressure of $Ar$ by $\frac{1}{2}$ to account for the change from 2 L to 4 L.
$0.237\text{ atm}*\frac{1}{2}=0.118\text{ atm}$