Which of the following does not describe a unit? a A unit is usually preceded by a number. b A unit compares what is being measured with a previously defined size. c The choice of unit depends on the quantity being measured. d A unit is not needed to find a solution to a problem.

In november 1987, a massive iceberg broke loose from the antartic ice mass and floated free in the ocean. the chunk of ice was estimated to be 98 mi long, 25 mi wide, and 750 ft thick. a typical backyard swimming pool contains about 24,000 gallons of water. how many of these pools could you fill from the water in this iceberg? (assume the iceberg is a rectangular solid of the above dimensions and consists of water only). express answer in scientific notation.