header bg

Scan QR code or get instant email to install app


A long distance runner does a first lap around a track in exactly 50 seconds. As she tires, each subsequent lap takes 20% longer than the previous one. How long does she take to run 3 laps in total?

A 182 seconds.

If the first lap takes 50 seconds, the second one takes 20% more, or \(T2=1.2 \times T1=1.2 \times 50 = 60\) seconds, where T1 and T2 are the times required for the first and second laps, respectively. Similarly, \(T3= 1.2 \times T2=1.2 \times 60 = 72\) seconds, the time required for the third lap. Add the times for the three laps: \(50 + 60 + 72 = 182\).

Related Information


Leave a Reply