Mark Frank is going snow boarding.
To get to the top of the mountain, he must ride the ski lift. Mark Frank gets in lift chair No. 10.
Exactly halfway up the ski lift, he passes chair No. 100.
Assuming all chairs are equally spaced apart, how many chairs did Mark Frank pass on his ascent?
ANSWER (updated 2.26.24)
To know how many chairs on the the ski lift total, first identify how many on each half of the lift cable (100  10 = 90). Then double it for the full amount. 180 chairs total on the ski lift.
Mark Frank gets on and off the ski lift at the lowest and highest points of it, respectively. He passes all chairs except his own. 179.
Sure, there are some potential missing variables in the challenge. Where specifically Mark Frank climbs aboard the ski lift. Total length of the ski lift. If the lift operators can pause the lift or engage a clutch on the chairs. If Mark Frank got off early or fell.
Make the necessary assumptions to solve this; state them if you need to.

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