If each term in the sum Asubscript1 + Asubscipt2 + AsubscriptN is either 7 or 77 and the sume equals 350 which of the following could be the value of N

38
39
40
41
42

well, first, think about the qualitative aspects of the sequence: if the sequence consisted entirely of 7's, then there would be fifty terms in the sequence. these answer choices are reasonably close to fifty, so it stands to reason that by far the majority of the terms will be 7's. therefore, try as few 77's as possible.

try only one 77:
remaining terms = 350 - 77 = 273
this would be 273 / 7 = 39 sevens
so ... you'd have one '77' and thirty-nine '7's

this works!

answer = c

Ron,

Could you also approach the question this way?

Since the units digit of 350 is zero, you know that the number of terms in the equation must be such that:

n*7 = number with units digit of zero

The only time this is true is if n is 10 or a multiple thereof, and 40 is the only answer that satisfies that.

mdh

wow, yeah, that's brilliant.
i feel so lame all of a sudden!

just goes to show - one of the hallmarks of gmat problems is that many (if not most) of them can be approached in a great variety of ways.
so, don't hesitate; pursue the first approach that seems legitimate, and you'll by likely to find success.