Question

A tablet takes 120 mins to charge. The fully charged tablet gives 180 mins of game time. If the battery is completely discharged but the power cord is plugged in, how long will it take to fully charge the battery, whilst playing a game?

Answer 1

Full charge will be done in 360 minutes.

Explanation:

A tablet takes 120 mins to charge.

So, in one minute the tablet is charged by
`(1)/(120) = 0.00833` parts.

Again, the fully charged tablet gives 180 mins of game time.

So, the tablet discharges fully in 180 mins gaming.

Then, in 1 minute of game playing the tablet is discharged by
`(1)/(180) = 0.00556` parts. (Appx.)

If charging and discharging by playing games both continue from the zero charge in the tablet, then in one minute it will be charged by (0.00833 - 0.00556) = 0.00277 parts. (Appx.)

Then full charge will be done in
`(1)/(0.00277) = 360` minutes. (Answer)