Answer :
The number of pages the student can read in a minute is an illustration of rates.
The time left to complete the whole book is 90 minutes
From the complete question, the student's rate is:
[tex]\mathbf{Rate = 50\ pages/hr}[/tex]
The number of pages is:
[tex]\mathbf{Total = 100\ pages}[/tex]
First, we calculate the time to read the whole book
[tex]\mathbf{Total\ Time = \frac{Total\ pages}{Rate}}[/tex]
[tex]\mathbf{Total\ Time = \frac{100\ pages}{50\ pages/ hr}}[/tex]
[tex]\mathbf{Total\ Time = 2\ hours}[/tex]
The number of the student has read is:
[tex]\mathbf{Pages = 25}[/tex]
Next, we calculate the time spent on the 25 pages
[tex]\mathbf{Time\ Spent = \frac{Pages}{Rate}}[/tex]
[tex]\mathbf{Time\ Spent = \frac{25\ pages}{50\ pages/hr}}[/tex]
[tex]\mathbf{Time\ Spent = 0.5\ hr}[/tex]
Convert to minutes
[tex]\mathbf{Time\ Spent = 30\ minutes}[/tex]
So, the time left is:
[tex]\mathbf{Time\ Left = Total\ Time - Time\ Spent}[/tex]
This gives
[tex]\mathbf{Time\ Left = 2\ hours- 30\ minutes}[/tex]
[tex]\mathbf{Time\ Left = 1\ hour, 30\ minutes}[/tex]
Convert to minutes
[tex]\mathbf{Time\ Left = 90\ minutes}[/tex]
Hence, the time left is 90 minutes
Read more about rates at:
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