Answer :
If it’s 600 feet up and the restaurant is 400 feet up then 600 feet is to much so we’re going to divide 600 feet by 2 to get 300 feet for 60 seconds (1m) If each 100 feet takes 20 seconds to get to then we’re gonna add 100 feet to it. Your answer should be 1m 20 seconds or 80 seconds