Hey all,

Couldn't figure this one out. A brief explanation would be very much appreciated. Thanks!

Some water was removed from each of 6 tanks. If standard deviation of the volumes of water at the beginning was 10 gallons, what was the standard deviation of the volumes at the end?

a. For each tank, 30% of water at the beginning was removed
b. The average volume of water in the tanks at the end was 63 gallons