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?
Ne me faites pas perdre mon temps, s'il vous plait ! J'ai besoin de ça de toute urgence !

Answer 1

Let time be x distance be y

• 140x=y-(1)
• 290x=360-y-(2)

Put value in eq(2)

$\\ \rm\longmapsto 290x=360-(140y)$

$\\ \rm\longmapsto 440x=360$

$\\ \rm\longmapsto x=1.2min$

Put it in eq(1)

• d=1.2(140)=168m