Question

10. An air pump used to extract air from a vessel removes one-tenth of the air at each stroke. What fraction of the original volume of air is left after the third stroke?

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Answer 1

Answer:

Instead of thinking "one third of the air in the tank is removed by each stroke", think "two thirds of the air in the tank is left after each stroke."

Then after 0 strokes there is 1 of the air left.

After 1 stroke there is 23 of the air left.

After 2 strokes there is 23⋅23 of the air left.

After 3 strokes there is 23⋅23⋅23 of the air left.

And so on.

Answer 2

Answer:

if you get your answer then kindly make me Brianlist

Step-by-step explanation:

Given that 1/2 of the air in a tank is removed with each stroke of a vacuum pump.

Air removed after first stroke = 1/2 of the tank volume

Total Air removed after second stroke = (1/2 + 1/(2x2)) of the tank volume

So, the total Air removed after fourth stroke = (1/2 + 1/4 + 1/8 +1/16) of the tank volume

=15/16

Have a nice day bro.