Thread: what is Sum of five odd number?

The question is:

What is sum of five odd numbers
a)Even
b)divisible by three
c)divisible by 5
d)a prime number
e)non of the above

The answer is none of above.
But i think the answer should be divisible by 5 because:
sum of x,x+2,x+4,x+6,x+8 is 5x + 20 which is always divisible by 5. Could anyone tell me what i am doing wrong here?

odd number=o

if o+o=even
o+o+o=odd
continuing in this way

the conclusion we get is
sum of odd numbers, even number of times is even

and

sum of odd numbers, odd numbers of times is odd

so that is the only information given in the question.

can u proceed further now.

Originally Posted by MikeNoob

But i think the answer should be divisible by 5 because:
sum of x,x+2,x+4,x+6,x+8 is 5x + 20 which is always divisible by 5. Could anyone tell me what i am doing wrong here?

It never said that the odd numbers were consecutive. For example: 1 + 3 + 5 + 7 + 11 = 27 which is not divisible by 5.

@Reckoner. Yeah never noticed that. Thanks for pointing it out.

Originally Posted by MikeNoob

The question is:

The answer is none of above.
But i think the answer should be divisible by 5 because:
sum of x,x+2,x+4,x+6,x+8 is 5x + 20 which is always divisible by 5. Could anyone tell me what i am doing wrong here?

Who said they have to be consecutive?

a) is obviously false, b), c) and d) are not necessarily true. So it's e) none of the above.

I Think It is not working as you describe your answer.
android apps source code

1+3+5+7+9 = 25

Let the 1st number be x, then sum of 5 odd number would be:x, x+1,x+3,x+5,x+7,x+9= 5x+25
then x=25/5= 5.
Therefore, answer would be option (c).