Question

David gets on the elevator at the 11th floor of a building and rides up at the rate of 57 floors per min.At the same time Albert gets on an elevator at the 51th floor of the same building at rides down at the rate of 63 floors per min.If they continue traveling at this rates,then at which floor will their paths cross

OPTIONS
A) 30 B) 19 C) 16 D) 31

Answer 1

The answer is 16. I hope that you are satisfied.

Answer 2

The anwer is 30. 
the time they both will cross each other is 20 sec.
since 20 sec. is 1/3 of a min.
therefore 57/3 and 63/3
= 19 and 21 
= 19 floor up from 11th floor and 21 floor down from 51 floor 
= 30 floor .