Answer: Famke uses her phone for 10 minutes and she charge it for 20 minutes .
Step-by-step explanation:
Let x be the number of hours Famke charges her phone.
Let y be the number of hours Famke uses her phone.
According to question, he charged it for twice the amount of time she used it.
So, it becomes

Number of points he gain while charging her phone = 2%
Number of points he loses while used her phone = 5%
Total points he lost = 10%
So, our equation would be

Put the value of x in the eq(2).

and x=2×10=20 minutes
Hence, Famke uses her phone for 10 minutes and she charge it for 20 minutes.