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How many minutes is it before 12 noon if 40 minutes ago it was three times as many minutes past 9 a.m.?

Thanks for help.

 Nov 8, 2021
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Let the number of minutes before noon ==M

 

Convert hours to minutes as follows:

12 x 60 ==720 minutes

9  x  60 ==540 minutes

 

720 - 40 - M ==540 + 3M

680 - M ==540 + 3M

680 - 540 ==3M + M

140 == 4M

M ==140 / 4 == 35 minutes to 12:00 noon

 

Check: 35 minutes to 12:00 noon is: 11:25 AM

40 minutes ago from 11:25 AM ==11:25  -  40 minutes ==10:45 AM

10:45 AM  ==60 + 45 ==105 minutes after 9:00 AM

3  x  35 minutes ==105 minutes after 9:00 AM - which balances

 Nov 8, 2021

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