A shop sells pens for \2andpencilsforand pencils forandpencilsfor$1.Ifyoubuy. If you buy .Ifyoubuy5itemsforitems foritemsfor$7,howmanypens(, how many pens (,howmanypens(p)andpencils() and pencils ()andpencils(n$) did you buy?
p=2,n=3p=2, n=3p=2,n=3
p=3,n=2p=3, n=2p=3,n=2
p=1,n=4p=1, n=4p=1,n=4
p=4,n=1p=4, n=1p=4,n=1