$3.20 is 2/9 so
$3.20/2=$1.60 is 1/9 so
$1.60*9=$14.40 is 9/9
Oh I didn't need to know that :)
I have 2/9 so I need 7/9 then I will have the whole lot
$3.20/2=$1.60 is 1/9 so
$1.60*7=$11.20
He needs another $11.20
OR I could have said
$14.40-$3.20=$11.20