word problem

[kritika.singhal1]

After the first term, each term in the sequence is five times greater than half the preceding term.
How to form the expression of the above statement, should it be
x/2+5x/2 or 5x/2?

[jnelson0612]

After the first term, each term in the sequence is five times greater than half the preceding term.
How to form the expression of the above statement, should it be
x/2+5x/2 or 5x/2?

Let's make up some number that could be this sequence:
First number= 2
Second number = (1/2)2 * 5 = 5
Third number = (1/2)5 * 5 = 12.5

I would just say Sn= 1/2(Sn-1) * 5

Please note, the above would have the "n" and the "(n-1)" in subscripts.

[shobana.rallapalli]

I am not sure I understood the logic. I interpreted the equation to be:

N2 = N1 + (5) (N1 divided by 2)
and
N3 = N2 + (5) (N2 divided by 2)

Thanks in advance.

[tim]

No, I believe "five times greater" in the GMAT context means "five times"; note that this is different from the way some people (including myself) interpret the term. I can’t actually recall any GMAT problems that use this language though, so the interpretation shouldn’t be a problem. Either way you interpret it though, you wouldn’t add 5 times n/2 onto n; if you adopted the second definition, you would add 5 times n/2 onto n/2..