If S is the sum of first "n" positive integers what is the

Question

If S is the sum of first "n" positive integers what is the value of n?

1. S221

Anonymous · Answer

E? 

combining both S can be >11 and <20.

still insuff.

carsen · Answer

If S is the sum of first "n" positive integers what is the value of n? 

1. S<20 - From this we know n can be either 1,2,3,4,5 (cannot be 6 as the sum will exceed 20) Hence S has to be between 1 to 5 (inlcusive). 
2. S^2>221 - If N is 4, then S is 10, which will give S^2=100, but this is smaller than 221. does not satisfy. The only number that satisfies this is if N=5 (then S is 15 and S^2 = 225)

The answer is C.

Anonymous · Answer

Its not consecutive integers, its first 'n' positive integers. Which can be 1+2+3 + 5 =11 or 2+5+6 which is 13, etc. Unless specified that its first n consecutive integers we cant assume anything. Even if we assume consecutive integers, it can be 4+5+6 which is 15 - the numbers also need not start with 1.

hardworker_indian · Answer

Though not specified, these are indeed consequetive integers.
When someone asks you for the first 3 positive integers, do you say, "2, 5, 6". No, we say "1, 2, 3" - since we have "first", we start with 1 and since it goes "first n positive", the (n+1)th number will never be smaller than the first n numbers.
So, inturn first n postive integers = first n positive consequetive integers

carsen · Answer

Hi

Hardworker is correct. Though is it not specifically said, it means first n positive integers...(starting from 1).

If someone says, 'Find the total of height of first 10 people, we start with 1,2,3,4,5..until 10'. In this question, the 'N' represents the 10. We have to find the 10, in here. 

Hence, when it is said first N +ve integers, we start with 1... I hope this is clear.

Regards

nzgmat · Answer

Yeah C,

n=5

and S = 15

and S^2=225

If S is the sum of first "n" positive integers what is the

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