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
1 and 2 together are sufficient but can someone actually work out the problem? What are the formulas through which n is derived?
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We need to determine the number of terms in the 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
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
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