arithmetic sequence
 Question: Arithmetic Sequence In an Arithmetic Sequence the difference between one term and the next is a constant. In other words, we just add the same value each time ... infinitely. In General we could write an arithmetic sequence like this: {a, a+d, a+2d, a+3d, ... } where: a is the first term, and d is the difference between the terms (called the "common difference") Rule We can write an Arithmetic Sequence as a rule: xn = a + d(n-1) Summing an Arithmetic Series  To sum up the terms of this arithmetic sequence: a + (a+d) + (a+2d) + (a+3d) + ... use this formula:  Question Given a 100 terms of arithmetic sequence, first term is  3, and the difference is 4, a new term is inserted between each tow terms and a new arithmetic sequence is received. What is the sum of terms of the new sequence?
2 People tried to answer this question

 40400
 39999
 79401
 20100

very good :)

you should sum up the terms of the new arithmetic sequence (not the given sequence).

think about the diffrence of the new sequence.

the number of terms in the new sequence is not 200 !!!

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