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You are a spy in a Spy Kid movie. You find yourself locked in a room (V = 60 m 3

ID: 890479 • Letter: Y

Question

You are a spy in a Spy Kid movie. You find yourself locked in a room (V = 60 m3). All of a sudden your watch (which is equipped with a poison gas sensor, among other things) detects a poison gas entering the room through an air duct (air flow rate = 3 m3/min). The gas will kill instantly once its concentration in the room reaches the lethal level of X ppm. The watch indicates that the concentration of the poison gas in the incoming air is 2X (i.e., 2 times the lethal level), but it is instantly diluted because the air in the room is well-mixed at all times. How much time do you have to escape?

Explanation / Answer

Solution :-

Rate of flow of the poisonus gas is 3 m3 / min and its concetration is 2X

lethal dose = X

volume = 60 m3

To reach the concnetration of the gas from 2X to X we need half of the total volume of the gas

that means we need 30 m3 of the gas to be filled in the room

we know

3 m3 = 1 min

30 m3 = ? min

30 m3 * 1 min / 3 m3 = 10 min.

Therefore time is 10 min to escape