12 bottles cost 9
And 3 dollars goes into 9 dollars three times, so to figure out how many u must do 12/3 = 4
So he can buy 4 bottles for three dollars
What is the cost per bottle?
Let x be cost of one bottle
12x=9
So x = 9/12 =3/4 = 0.75 cent
We know that if one bottle is 0.75 cent, then 7 bottles must be 0.75 x7= $5.25
