The key concept here is percent of a whole — specifically, recognising that the difference in percentages between two people directly translates to a difference in dollar amounts, without needing to find the actual value of p.
Step 1 — Identify what "p percent" and "(p+6) percent" mean
Ana receives p% of the total prize. Bruno receives (p+6)% of the total prize. The difference between their shares is exactly 6% of the total — notice that p cancels out completely. You don't need to know what p is.
Step 2 — Set up the equation using the dollar difference
Bruno received $120,000 more than Ana, and that gap represents 6% of the total prize pool.
6% × Total = $120,000
Total = $120,000 ÷ 0.06 = $2,000,000
Step 3 — Calculate Charles's share
Charles received 15% of the total.
15% × $2,000,000 = $300,000
Answer: C
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Common trap: Most students try to find the value of p first. They write equations like p + (p+6) + 15 = 100 and get stuck because there are other friends whose percentages are unspecified. The question never tells you the group's total share adds to 100% for just these three people — and you don't need it to. The moment you spot that Bruno − Ana = 6% of total, you're done.
Takeaway: Whenever two people receive x% and (x+k)% of the same total, their dollar difference equals exactly k% of that total — use that directly rather than chasing the individual percentage values.
(Kavya | 725 on GMAT Focus Edition)