Question: http://good-interview-puzzles.blogspot.com/2011/09/calculate-distance.html
It is given that the platoon and the last person moved with uniform speed. Also,they both moved for the identical amount of time. Hence, the ratio of the distancethey covered - while person moving forward and backword - are equal.Let's assume that when the last person reached the first person, the platoonmoved X meters forward.Thus, while moving forward the last person moved (50+X) meters whereas theplatoon moved X meters
Similarly, while moving back the last person moved [50-(50-X)] X meterswhereas the platoon moved (50-X) meters.
Now, as the ratios are equal,(50+X)/X = X/(50-X)(50+X)*(50-X) = X*XSolving, X=35.355 metersThus, total distance covered by the last person= (50+X) + X= 2*X + 50= 2*(35.355) + 50= 120.71 metersNote that at first glance, one might think that the total distance covered by thelast person is 100 meters, as he ran the total lenght of the platoon (50 meters)twice. TRUE, but that's the relative distance covered by the last person i.e.assuming that the platoon is stationary
It is given that the platoon and the last person moved with uniform speed. Also,they both moved for the identical amount of time. Hence, the ratio of the distancethey covered - while person moving forward and backword - are equal.Let's assume that when the last person reached the first person, the platoonmoved X meters forward.Thus, while moving forward the last person moved (50+X) meters whereas theplatoon moved X meters
Similarly, while moving back the last person moved [50-(50-X)] X meterswhereas the platoon moved (50-X) meters.
Now, as the ratios are equal,(50+X)/X = X/(50-X)(50+X)*(50-X) = X*XSolving, X=35.355 metersThus, total distance covered by the last person= (50+X) + X= 2*X + 50= 2*(35.355) + 50= 120.71 metersNote that at first glance, one might think that the total distance covered by thelast person is 100 meters, as he ran the total lenght of the platoon (50 meters)twice. TRUE, but that's the relative distance covered by the last person i.e.assuming that the platoon is stationary
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