Which statement is true about this equation? y = 2^x+ 4
A. It represents a function only.
B. It represents a relation only.
C. It represents both a relation and a function.
D. It represents neither a relation nor a function.

C. It represents both. A relation and a function

First the 5 and 10 minute people cross, then the 5 minute person goes back with lantern ( so 15minutes is used ) and you have 5,20 and 25 still to cross then the 20 and 25 minute goes across ( which means 25 +15 = 40mins is used ) then 10mintue person ( which has already crossed ) , goes back to the start with the lantern ( which means 40+10 =50mintues used ). then the 5 and 10mintue cross ( 10+50 =60mintues ) and all have crossed .