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Tiffany pays $40 for 160 minutes of talk time on her cell phone. How many minutes of talk time does she get per dollar?

Answer 1

Everly Taylor

#4# minutes per dollar

This is a "rate" problem.

So you have to find the rate as #x# minutes per 1 dollar.

What you do is you divide minutes by dollars:

#160 mins div $40#

so that you can get #x# minutes per dollar.

#160/40 = 4#

So the answer is # 4 # minutes per dollar.

Or:

You can also show where the #$1# comes from:

#160# minutes for #$40" "larr div# both by #40#

#160/40# minutes for #($40)/40#

#" "4# minutes for #$1#

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Answer 2

Benjamin Altschul

Tiffany gets 4 minutes of talk time per dollar.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.