Acylinder is full at 471 cm3 and has a radius of 5 cm. it currently contains 314 cm3 of water. what will the difference in the height of the water be when the cylinder is full? use 3.14 to approximate pi.

Volume of a cylinder = π r² h

fully filled w/ water:
471 cm³ = 3.14 * (5cm)² * h
471 cm³ = 3.14 * 25cm² * h
471 cm³ = 78.5 cm² * h
471 cm³ / 78.5 cm² = h
6 cm = h  

partially filled with water
314 cm³ = 78.5cm² * h
314 cm³ / 78.5 cm² = h
4 cm = h

6 cm - 4 cm = 2 cm the difference in the height of the water.

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.