car traveling 90 feet per second

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Nekkamath

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A car that is traveling 90 feet per second is traveling how many miles per hour? There are 5280 feet in 1 mile. Express your answer to the nearest whole number.

I figured 90 feet per second is 324000 feet per hour. I divided 324000 by 5280 and got 61 miles per hour.
 
Just set things up so the undesired units cancel:

. . . . .\(\displaystyle \frac{90\, ft}{1\, sec}\,\times\, \frac{60\, sec}{1\, min}\,\times\, \frac{60\, min}{1\, hr}\,\times\, \frac{1\, mi}{5280\, ft}\)

...which, after cancelling, yields:

. . . . .\(\displaystyle \frac{90\, \times \, 60 \times \, 60 \, mi}{5280\, ft}\, = \, 61.363636... \, mph\)

So, after rounding, your answer is correct. :D

Eliz.
 
Ok, so just multiply 90 (Is that the number you used?) by 60.

90 miles per second
60 seconds per minute

90 x 60 = 4200 miles
 
horseluvr84 said:
Ok, so just multiply 90 (Is that the number you used?) by 60.

90 miles per second
60 seconds per minute

90 x 60 = 4200 miles<<<< Incorrect
Click to expand...
 
horseluvr84 said:
I keep meaning to say, 90 x 60 is 5400
Click to expand...

Now your multiplication is correct - but it is solving wrong problem.

first of all - the given speed 90 ft/sec

Then the question asked for converted speed (in miles/hour) - not distance.
 
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