"David gets on the elevator at the 11th floor of a building and rides up at the rate of 57 floors
Channel: Doubtnut
Date: 2020-04-05

"David gets
 on the elevator at the 11th floor of a building and rides up at
 the rate of 57 floors per minute. At the same time, Albert gets on an
 elevator at the 51st floor of the same building and rides down at
 the rate of 63 floors per minute. If they continue travelling at these rates,
 then at which floor will their paths cross?
(a) 19th (b) 28th (c) 30th (d) 37th"