28 . D
Expand the expression you’re solving for and see what happens:
29 . D
Sketch (or visualize) the situation. Before more water is added, the water level is half of 25,
or 12.5 meters:
As water is poured in, the rectangular solid that represents the water gets taller, while the
dimensions of the base stay the same. As water is poured in for 9 seconds at the rate of 12
cubic meters per second, the amount added is 9 × 12 = 108 cubic meters. With a base of 3