Respuesta :
Phone card = $20
You need to minus 17.92 from 20 = $2.08
$2.08 / 0.13 = how many minutes
= 16
You need to minus 17.92 from 20 = $2.08
$2.08 / 0.13 = how many minutes
= 16
the call lasted 16 mins, i used trial and error and the came across 16x.13=2.08 and then you add 17.92 plus 2.08 and that gives you 20