Question

Which set of ordered pairs could be generated by an exponential function?
(1, 1), (2, one-half), (3, one-third), (4, one-fourth)
(1, 1), (2, one-fourth), (3, one-ninth), (4, one-sixteenth)
(1, one-half), (2, one-fourth), (3, one-eighth), (4, one-sixteenth)
(1, one-half), (2, one-fourth), (3, one-sixth), (4, one-eighth)

Answer 1

The third set: (1, 1/2), (2, 1/4), (3, 1/8), (4, 1/16).

Reason: an exponential sequence has a constant ratio between successive y-values. Here each term is half the previous (ratio = 1/2), so y = (1/2)^x fits the points. The other sets do not have a constant multiplicative ratio.