Answer:
5 levels
Explanation:
To know the rate of her beating levels yesterday, divide the # of minutes she played (27 minutes) to the # of levels she beat (3 levels).
So she played for 9 minutes to beat a single level.
Since she will try to beat levels the same rate as yesterday, you will have to divide the #of minutes her parents let her play (45 minutes) to yesterday's rate (9 minutes per level).
Britney should beat 5 levels today if she wants to beat levels at the same rate as yesterday's.