



 
Hi Juan, The formula for arithmetic sequence is a_{n}=a_{1}+(n1)d where a_{1} is the first term, a_{n} is the nth term in the sequence and d is the common difference. So for the fourth term we can write it as 16=2+(41)d What is the value of d? Once d is found, you can use the same formula for the nth term 11998 to find how many terms are in the sequence. Hope this helps, Janice  


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