Hi All,
This is an example of a "limit" question (a prompt that asks you to solve for the "lowest" or "highest" possible value) and Brent's solution is perfect (it's exactly how I would approach this question). Sometimes Quant questions are more about "playing" with a series of restrictions and saying "what if…?" than doing lots of algebra.
There is an algebra approach to this prompt, but it still involves aspects of what Brent showed in his approach (TESTing VALUES, minimizing values so you can maximize one of them):
Since we're dealing with 5 DIFFERENT positive 2-digit integers, to maximize 1 of them, we have to minimize all of the others.
I'll call the smallest 2-digit integer….X
So the next 3 smallest would be….(X+1), (X+2) and (X+3)
Those 4 values sum to 4X + 6
Since the sum of all 5 terms = 130, the 5th value (the biggest one) is….130 - (4X+6)
If you make X the smallest positive 2-digit number possible, you'd have X=10. Plug THAT value into the calculation and you get…
130 - (40+6) = 84
Final Answer:
While I would NOT recommend approaching the question in this way (since it requires so much more work and time), it does get you to the correct answer.
GMAT assassins aren't born, they're made,
Rich