Physics help?

"A tortoise can run with a speed of 10.5 cm/s, and a hare can run 19.4 times as fast. In a race, they both start at the same time, but the hare stops to rest for 121 seconds. The tortoise wins by a shell (18.7 cm). How long does the race take?"

For the tortoise, s = v*t = 0.105m/s * t

where s is the race length, v his velocity, and t the race time.

For the hare, s - 0.187m = 19.4*0.105m/s*(t - 121s)

Subtract the second from the first (and dropping units for ease):

0.187 = 0.105*t - 19.4*0.105*t + 19.4*121*t = -1.932*t + 246.477

t = (246.477 - 0.187) / 1.932 = 127.48 s ◄

Check:

the tortoise goes s = 0.105m/s * 127.48s = 13.39 m

and the hare goes S = 19.4 * 0.105 * 6.48s = 13.20 m √√√

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