Answer:
[tex]2\frac{2}{5}[/tex] hours, or 1 hours and 24 minutes
Step-by-step explanation:
4/5 battery remaining
drains at rate of 1/3 per hour
[tex]\frac{1}{3}h=\frac{4}{5}\\\frac{3}{1}(\frac{1}{3}h)=\frac{3}{1}*\frac{4}{5}\\h=\frac{3*4}{1*5}=\frac{12}{5}=2\frac{2}{5}[/tex]
He has 2 2/5 hours or 2 hours and 24 minutes left until his phone dies. (A fifth of an hour is 12 minutes and we have 2/5 to deal with, so 12 times 2 is 24 mins.)