Question

It takes Arnold 10 minutes to climb the stairs from the ground floor to the 25th floor. Find the time it takes to climb from the ground floor to the 5th floor.

Answer 1

2 minutes

Explanation:

Let's find Arnold's climbing rate, in floors/minute.

We know he climbs from ground (0) to the 25th floor (25) in 10 minutes.

Express that as floors/min: He climbed 25 floors/10 minutes. That reduces to 2.5 floors/minute. We can invert that and also state he has a rate of (1 minute/2.5 floors).

If we assume Arnold rate is constant for all floors (not likely, but we have no better information), we can say that:

(5 floors)*(1 minute/2.5 floors) = 2 minutes to climb 5 floors

[The original rate of 2.5 floors/minute can also be used, but the calculation would be:

(5 floors)/(2.5 floors/minute) = 2 minutes [I dislike division, so I u=inverted the rate factor]