Tracy wants to buy some pies for her sisters and she has a budget of $82 to spend on $5 apple pies, $4.5 banana pies, and $5.5 chocolate pies. She wants to buy 16 pies for her
sisters and must buy as many chocolate pies as apple pies and banana pies combined.
How many of each item should she buy?

5 of each item is how much she should buy

Step-by-step explanation:

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb