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Ten percent of the class period was spent taking roll and making announcements. If there were 45 minutes that remained, how long is the class period? 

 

Show answer but also explain it plz so I understand it

 Jan 31, 2018

Best Answer 

 #1
avatar+7563 
+3

Let's call the length of the class period  " p ".

 

From the problem statement, we can make this equation:

 

p  -  10%  of  p   =   45 minutes

 

p  -  0.1p   =   45 minutes

 

0.9p   =   45 minutes      (In other words, 90% of the class period is 45 minutes.)

                                       Divide both sides of the equation by  0.9 .

p   =   45 / 0.9 minutes

 

p   =   50 minutes          smiley

 Jan 31, 2018
 #1
avatar+7563 
+3
Best Answer

Let's call the length of the class period  " p ".

 

From the problem statement, we can make this equation:

 

p  -  10%  of  p   =   45 minutes

 

p  -  0.1p   =   45 minutes

 

0.9p   =   45 minutes      (In other words, 90% of the class period is 45 minutes.)

                                       Divide both sides of the equation by  0.9 .

p   =   45 / 0.9 minutes

 

p   =   50 minutes          smiley

hectictar Jan 31, 2018
 #2
avatar
+1

Thx 

 Jan 31, 2018

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