the cost of a long distance call lasting 4 minutes and 20 seconds is $ 23.40.At this rate what was the cost of a call lasting 6 minutes 30 seconds

Question

this is a question about rate and is of level 6.please give me detailed explantion,i need it.

thankyou

Answer 1

"cost of a long distance call lasting 4 minutes and 20 seconds is $ 23.40"

 

The "unit rate" of this call is in dollars per minute.  That is, $23.40 / (4 1/3 minutes).

     $23.40 / (13/3 minutes)       [convert to improper fraction]

     23.40 * (3/13) $/minute      [to divide by fraction, invert and multiply]

      $5.40 /minute

 

To talk for 6 1/2 minutes "at this rate," just multiply:

    ($5.40 per minute) * (6 1/2 minutes)

     $5.40 * 13/2      [minutes cancel out]

      $35.10

Answer 2

Ayesha,

 

The ratio will look like this:

 

(4min 20sec)/$23.40 = (6min 30sec)/$x

 

To solve this, you need to change the times to something we can mathematically use. e.g., you can change 4min 20 secs to either 4 and 1/3 or 13/3 minutes or to 260 secs since 4 minutes is 240 secs.  If you do the same for the second time, then the ratio looks like:

 

260sec/$23.40 = 390sec/$x (390sec is 6mins 30sec)

 

Then cross multiply:

 

260x = 390(23.40)

 

I'll let you do the rest.

Answer 3

You can solve this using a proportion.  First step is to convert the minutes to decimals.

 

4 minutes 20 seconds = 4 + 20/60 = 4.33 minutes

6 minutes 30 seconds = 6 + 30/60 = 6.5 minutes

 

Now set up the proportion of time/cost.

 

4.33 minutes/$23.40 = 6.5 minutes/$x

 

6.5(23.40) = 4.33x

152.1 = 4.33x

35.1 = x

 

So the call costs $35.10.