An olympic swimmer is having his laps timed during practice. To be aware of his progress, the results are shown as order pairs (l, t) below: (1,19), (2,38), (3,57) (4,76). Which equation represents t, the time in seconds, as a function of l the number of laps that the swimmer has finished?

Question

An olympic swimmer is having his laps timed during practice.  To be aware of his progress, the results are shown as order pairs (l, t) below:  (1,19), (2,38), (3,57) (4,76).  Which equation represents t, the time in seconds, as a function of l the number of laps that the swimmer has finished?

A: t(l) = l + 19
B:  l(t) = t/19
C: l(t) = 19t
D:  t(l) = 19l

Is it "C"

MathMate · Answer

"represents t, the time in seconds, as a function of l the number of laps"
means that l is the independent variable, and t(time) is the dependent variable. Therefore you only have a choice between A and D. Choose the one with the correct relation.