If we know that 30% of the time is used after 9 minutes we can write this mathematically as:

By solving for x we can determine the total time allowed to play games and so:

The total time allowed to play games is 30 minutes. Since 9 minutes have lapsed 30-9=21 minutes left to play.
Step-by-step explanation:
<u>1</u><u> </u>*9^2 + 4
3
<u>1</u><u> </u>* 81 + 4
3
<u>1</u><u> </u>* 85
3
<u>85</u>
3
=28
Answer:
A
Step-by-step explanation: