A new anesthetic agent with a vapor pressure of 150 torr at 20C is placed in a copper kettle vaporizer and the flow meters are set at:

Oxygen 2L Nitrous oxide 3 L Flow through kettle 200 ml Temperature 20C

Under these conditions, the concentration of the anesthetic emerging from the gas machine is

(A) 0.1%
(B) 0.5%
(C) 0.75%
(D) 1%
(E) 2%

Have fun with this one!