Answer
a) Yes
b) Yes
c) No
Work Step by Step
a) Given that Apple sold upwards of 22 million iPods in the period of time, it is reasonable to represent the data with 5 significant figures, approximating the value to the nearest thousand.
b) It is appropriate to represent average rainfall with 3 significant figures. Any more precision than 0.1 inches is likely unnecessary.
c) The grade point average has 6 significant figures, which is not appropriate. It is unlikely that this information would have to be known to such a degree of precision.