Marnie conducted an experiment using a bag of 12 marbles containing an equal number of blue, red, and green marbles. She randomly chose one marble, noted the color, and returned the marble to the bag. Marnie did this for a total of 20 trials. The table below shows the results. Event
Count
Blue
7
Red
8
Green
5

What was the experimental probability of choosing a blue marble from a bag?
StartFraction 7 over 20 EndFraction
StartFraction 7 over 13 EndFraction
StartFraction 7 over 12 EndFraction
StartFraction 7 over 8 EndFraction

Submarines control how much they float or sink in the ocean by changing the volume of air and water contained in large ballast tanks. when the tanks are completely full of water, the submarine increases its overall mass and sinks down to the bottom. when the tanks are completely full of air, the submarine reduces its overall mass and floats to the surface. depending on the density of the seawater surrounding the submarine, it will pump seawater in or out of the tanks in order to achieve the same overall density as the sea water and float neutrally in the water. the volume of the submarine never changes. when the tanks are completely full of water, a submarine with a volume of 7.8\times10^3\text{ m}^37.8×10 3 m 3 7, point, 8, times, 10, start superscript, 3, end superscript, space, m, start superscript, 3, end superscript has a total mass of 8\times10^6\text{ kg}8×10 6 kg8, times, 10, start superscript, 6, end superscript, space, k, g. the density of the seawater is 10^3\text{ kg/m}^310 3 kg/m 3 10, start superscript, 3, end superscript, space, k, g, slash, m, start superscript, 3, end superscript. to make that submarine float neutrally, and neither float nor sink in the ocean, what volume of water does that submarine need to subtract from its tanks?