Mobile phone

[kate]

Jenny has a mobile phone which battery can keep working for 6 hours in talks or 210 hours waiting. When she went to a international excursion with bus in the morning of the first day its battery was full, and in the evening the phone turned off. If you know that she talked exactly the half time of the trip, find how many hours did she travelled.

[shyamjayakannan]

battery drain rate while talking = [tex]\frac{100}{6}=\frac{50}{3}[/tex] %/hr and while waiting = [tex]\frac{100}{210}=\frac{10}{21}[/tex] %/hr. Let the total time of the trip be [tex]t[/tex].

So, [tex]\frac{t}{2}\times\frac{50}{3}+\frac{t}{2}\times\frac{10}{21}=100\Rightarrow\boxed{t=11.66hr}[/tex]