A certain business has implemented a new incentive plan whereby employees earn tokens for every sale they make.

For 1 sale, an employee earns 1 token.
For 2 sales, an employee earns 9 tokens.
For 3 sales, an employee earns 21 tokens.
For 4 sales, an employee earns 37 tokens.

Which recursive equation represents the pattern?

an = an – 1 + 4n
an = an – 1 + 4(n + 1)
an = an – 1 + (n + 4)
an = an – 1 + (n – 4)

Question

A certain business has implemented a new incentive plan whereby employees earn tokens for every sale they make.

For 1 sale, an employee earns 1 token.
For 2 sales, an employee earns 9 tokens.
For 3 sales, an employee earns 21 tokens.
For 4 sales, an employee earns 37 tokens.

Which recursive equation represents the pattern?

    an = an – 1 + 4n
    an = an – 1 + 4(n + 1)
    an = an – 1 + (n + 4)
    an = an – 1 + (n – 4)

anonymous · Answer

The answer should be $$a_n=a_{n-1} + 4n$$
As you should realise the difference between each term in the sequence is increasing by multiples of 4, hence you get +4n.

anonymous · Answer

Oh, if you hadn't realised, you should treat your question as a sequence of terms.
So for the 
1st term, you get 1
2nd term, you get 8 ...etc, so you get the sequence:
1,  9  ,  21,  37 ...