Question

Which function represents the number of seconds, s, in d days? (Hint: The number seconds in a day is 24 × 60 × 60 = 86,400.)

Answer 1

f(d)=86,400·d
if you set 1 day (d=1) you get f(1)=86,400 sec
if you set 1 day (d=2) you get f(2)=172,800 sec
...etc.