Question

When Famke charges her phone, it gains 2 percentage points each minute. When Frmke uses her phone, it loses 5 percentage points each minute. Once, Famke used her phone for some time, and then charged it for twice the amount of time she used it. In the end, her phone lost 10 percentage points. How long did Famke use her phone and how long did she charge it?

Answer 1

It only lasts for 20 minutes, and takes 50 minutes to charge (She needs a new phone). 100-(10*5)=50
50+(20*2)=90%
she uses it for 10 minutes and charges it for 20 minutes.