The concept being tested here is Data Sufficiency with percent increase and an inequality — a combination that trips up a lot of people because they instinctively try to solve for exact weights instead of just checking whether the condition x > 20 can be confirmed or ruled out.
Quick setup: If Pedro weighs x% more than Pablo, then Pedro = Pablo × (1 + x/100). The question asks: is x > 20?
Step 1 — Translate the question into algebra.
Let Pablo's weight = P. Then Pedro's weight = P(1 + x/100).
We're also told Pedro < 90. The question is just: is x > 20?
Step 2 — Test Statement (1): Pedro weighs 16 pounds more than Pablo.
This tells us Pedro − Pablo = 16, so x/100 = 16/P, meaning x = 1600/P.
For x > 20, we'd need P < 80.
But we only know Pedro < 90 — Pedro could be 88 (so Pablo = 72, x ≈ 22) OR Pedro could be 17 (so Pablo = 1, x = 1600). Both satisfy Pedro < 90 and the 16-pound difference.
The trap here is assuming that "16 pounds more" uniquely pins down x. It doesn't — x depends entirely on Pablo's actual weight, which we don't know.
Statement (1) alone is Not Sufficient.
Step 3 — Test Statement (2): If Pedro's weight decreased by 18%, he'd still weigh more than Pablo.
This means 0.82 × Pedro > Pablo.
Since Pedro = Pablo(1 + x/100), substituting:
0.82 × Pablo(1 + x/100) > Pablo
→ 0.82(1 + x/100) > 1
→ 1 + x/100 > 1/0.82 ≈ 1.2195
→ x/100 > 0.2195
→ x > 21.95
So x is definitely greater than 20. Statement (2) alone is Sufficient.
Answer: B
The common trap: Students spend time trying to find Pablo's exact weight using Statement (1) instead of recognizing it's a relationship question. In DS, always ask "can I answer yes/no?" before solving for values.
Takeaway: When DS asks about a percent relationship, set up the inequality first — if one statement resolves it completely without needing a specific value, that's your answer.
— Kavya | 725 (Q90, V85, DI79) | GMAT Focus Edition