David\'s phone battery level drops 1 percentage point every 10 minutes when he i

Question

David's phone battery level drops 1 percentage point every 10 minutes when he is not playing a game on it. When David does play a game on his phone, the phone battery level drops 3 percentage points every 10 minutes. On a particular day, the phone battery level was at 100% at 12:00 noon and at 16% at 6:00 PM. If David did not charge his phone during this time, how many minutes did he spend playing the game between 12:00 noon and 6:00 PM on that day?

Note: Please provide step by step explanation.

Explanation / Answer

Let, x minutes be spent playing the game and y minutes not playing

So,

x+y=6*60=360

Converting minutes into units of 10 minutes is done by dividing by 10.

So,

3*(x/10)+y/10=84

3x+y=840

Solving gives

x=240,y=120

So,

240 minutes were spent playing

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.