Justin takes the underground train to work and uses an escalator at the railway station. If Justin runs up 7 steps of the escalator, then it takes him thirty seconds to reach the top of the escalator. If he runs up 13 steps of the escalator, then it takes him only twenty-one seconds to reach the top.
How many seconds would it take Justin to reach the top if he did not run up any steps of the escalator at all?
Answer
If he runs up 7 steps, then he needs 30 seconds to reach the top.
If he runs up 13 steps, then he needs 21 seconds to reach the top.
The 6 additional steps take 9 seconds.
Therefore, each step takes 1.5 seconds.
Total steps in escalator = 7 + 30.0 / 1.5 = 27 or Total steps in escalator = 13 + 21.0 / 1.5 = 27.
If Justin did not run up any steps at all, he would reach the top of the escalator in 40.5 seconds.
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