Question

Two groups of tourists are on the same floor of a skyscraper they are visiting, and they board adjacent elevators at the same time. The first group is headed up at a speed of 140 meters per minute. The second is headed down at a speed of 290 meters per minute. How long will it be before the elevators are 360 meters apart?

Answer 1

Let time be t , distance be d

• 140t=d-(1)
• 290t=360-d-(2)

Put value in eq(2)

$\\ \rm\longmapsto 290t=360-(140t)$

$\\ \rm\longmapsto 440t=360$

$\\ \rm\longmapsto t=1.2min$