GMATPrep Test 1 - DS Sequence

medenica wrote:If the terms of a squence are t1, t2, t3, ... , tn, what is the value of n?

1) The sum of the n terms is 3,124
2) The average of the n terms is 4

We need to determine the number of terms in the sequence.

Statement One Only:

The sum of the n terms is 3,124.

Since we don’t know anything about each individual term, we can’t determine the number of terms in the sequence. Statement one alone is not sufficient.

Statement Two Only:

The average of the n terms is 4.

Since we don’t know anything about each individual term, we can’t determine the number of terms in the sequence. Statement one alone is not sufficient.

Statements One and Two Together:

Since sum = quantity x average, we have:

3,124 = n x 4

n = 3,124/4 = 781

Answer: C