Answer:
let's take the postion of sea level 0
such that
syds on a cliff 43 ft above sea level
his position = 43 ft
Ingrid is 17 feet below sea level so his position = 17 ft in the opposite direction as that of Syd.
since syd is 43 feet away from sea level, that is 0, and sea level is 17 feet away from Ingrid.
distance between syd and Ingrid = 43 + 17
= 60 ft