Question

Nathan boards an elevator in the lobby that is headed up at 160 meters per minute. Meanwhile, 210 meters above, Joey boards an adjacent elevator headed down at 230 meters per minute. How long will it be before Nathan and Joey pass each other?

Answer 1

Let time be t , distance be d

• 160t=d-(1)
• 230t=210-d-(2)

Put value in eq(2)

$\\ \rm\longmapsto 230t=210-(160t)$

$\\ \rm\longmapsto 70t=210$

$\\ \rm\longmapsto t=30min$