A new high-tech transportation system is to be built connecting a city at sea level and a suburb 3,500 feet above sea level. The maximum allowable grade is 3 percent, which means that the track for the new system can ascend no more than 3 feet for every 100 feet of horizontal length. What is the minimum whole number of feet of track needed for the new system?

A) 113,167 ft
B) 116,615 ft
C) 116,615 ft
D) 116,667 ft
E) 120,167 ft

How many times does this track need to go up 3 feet?

3500/3 = 1166.666…

Every time it goes up 3 feet, it needs to have 100 feet of horizontal length, so multiply that by 100:

100 × 1166.666… = 116,667

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