This is called an "arithmetic series".
Each term in an arithmetic series ALWAYS has a difference of "d" between each term. Subtract any term in this sequence by the one that preceded it and the answer is always d=(I'll let you figure this one out).
If you want to calculate the actual cost of 100 apples, you need to find the sum of the first 10 terms (as each term represents the price of 10 apples in sequence). you can find this easily by plugging the first and last term into a simple equation:
For a FINITE arithmetic sequence,
Sn = (n/2)(a1 + an)
a1=first term, an=last term, n=the total number of terms being added.
Plug these figures in and what do you get?
now, to create *an equation*
The nth term of an arithmetic sequence can be found using a couple of general formulas, but here's the best one you should use (I recommend you look into this)
The nth term of an arithmetic sequence has the form an = dn + c
where c = a1 - d
You take it from there.
Last edited by strumbore
on Sat Jan 12, 2013 9:38 am, edited 1 time in total.