Total is $18.72 so the shopper would need to buy 6 of the 8 packs!!!
8, because it's the has the greatest difference from the number average.
K, so areitmetic
an=a1+d(n-1)
a1=first term
d=common differnce
we are given
a1=2 and 3/4
6th term is 3 and 7/12
so
a6=3 and 7/12=2 and 3/4+d(6-1)
3 and 7/12=2 and 3/4+d(5)
minus 2 and 3/4 both sides
10/12=5d
divide both sides by 5 or multiply both sides by 1/5
2/12=d
1/6=d

or

that is the rule