Question

Every night Mary spends 3 hours doing homework, 30 minutes practicing the piano, and 35 minutes talking on the phone, what is the total number of minutes Mary spend doing these activities

Answer 1

3 hours = 180 minutes
180 + 30 = 210 + 35 = 245

She spends 8 hours and 5 minutes, or 245 minutes doing these activities.

Answer 2

Add the minutes first
35 + 30 = 65
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Now find the minutes of 3 hours
60 x 3 = 180
180 mins in 3 hours
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180 + 65 = 245
She spends 245 minutes doing these activities