Grrr... 'Tortise runs at 10cm/s; hare runs 20 times as fast'

E

eulB

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Jan 20, 2005
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I dont care so much as to an answer. I just want to know HOW to solve this type of problem:

I keep getting 2204 seconds (the answer must be in seconds)

A tortise can run with a speed of 10.0 cm/s, and a hare can run exactly twenty times as fast. In a race, they both start at the same time, but the hare stops to rest for 2.oo min. The tortise wins by 20.0 cm. How long does the race take?
 
Re: Grrr word problem

eulB said:
I dont care so much as to an answer. I just want to know HOW to solve this type of problem:

I keep getting 2204 seconds (the answer must be in seconds)

A tortise can run with a speed of 10.0 cm/s, and a hare can run exactly twenty times as fast. In a race, they both start at the same time, but the hare stops to rest for 2.oo min. The tortise wins by 20.0 cm. How long does the race take?
Click to expand...

Please show us your work so that we can critique it properly.
 
so if the hare travels 20 times as fast then he should be able to travel 200 cm/s

In that two miniute "rest" the hare could ave gone 24000 cm (200cm/s x 120s)

It would take the snail 2400 seconds to go that 24000 cm and then i add 2 seconds because he wins by 20 cm.
 
If the turtle travels 10t cm, then in the same time the rabbit travels

200(t-120). But the difference is 20 cm.

10t-200(t-120)=20. Solve for t.
 
Can you please explain what each number means and why/how you set up that equation. I have three similar problems i need to do and i would like to complete them of my own accord.
 
eulB said:
Can you please explain what each number means and why/how you set up that equation. I have three similar problems i need to do and i would like to complete them of my own accord.
Click to expand...

Let t = time (in seconds) that it takes the turtle to finish the race.

In t seconds, the turtle covers 10t cm.

The hare runs 20 times as fast, so the hare covers 200 cm each second.

The hare rests for 2 minutes, or 120 seconds. So, when the turtle has run t seconds, the hare has run t - 120 seconds. At 200 cm each second, the distance run by the hare is 200(t - 120) seconds.

The turtle wins by 20 cm. So, the turtle's distance is 20 cm more than the hare's distance:

10t - 200(t - 120) = 20
 
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