Answer :
John paid $0.10 more per ballon
John
$4.80/3=$1.60 per ballon
Karen
$6/4=$1.50 per ballon
$1.60-$1.50=$0.10
John
$4.80/3=$1.60 per ballon
Karen
$6/4=$1.50 per ballon
$1.60-$1.50=$0.10