A flower vendor bought 200 flowers for ₹800. 20 flowers withered and became unsellable. At what price per flower should he sell the remaining flowers to earn a profit of 30% on his total cost?

Correct — C. The 30% profit is on the full cost of all 200 flowers.

Target revenue: 800 × 1.30 = ₹1,040
Flowers left to sell: 200 − 20 = 180

Price per flower: 1,040 ÷ 180 = 5.777…
Rounded to paise: ₹5.78 → option (c)
Check: 180 × 5.78 = ₹1,040.40, a profit of just over 30%

Why the others are wrong

• (a)
  ₹7.85 — ₹7.85 overshoots. 180 flowers at ₹7.85 bring in ₹1,413, a profit of about 77% on ₹800, far above the 30% asked for.
• (b)
  ₹6.54 — ₹6.54 also overshoots. 180 × 6.54 = ₹1,177.20, a profit of about 47% on the ₹800 cost, not 30%.
• (d)
  ₹3.82 — ₹3.82 is below cost. 180 × 3.82 = ₹687.60, less than the ₹800 paid, so it is a loss of about 14%, not a profit.

When part of the stock is lost, the cost stays the same but fewer units carry it. Fix the target revenue from the full cost first, then divide by the units that can actually be sold.

Here ₹800 bought 200 flowers but only 180 can be sold, so each sold flower must recover more than the ₹4 it cost. The target price is 1,040 ÷ 180, not 1,040 ÷ 200.

Key facts

• Selling price for a p% profit = cost × (100 + p)⁄100, so 800 × 130⁄100 = 1,040.
• Cost per flower bought = 800 ÷ 200 = ₹4.
• Revenue needed per sellable flower = 1,040 ÷ 180 = 52⁄9 ≈ ₹5.78.

Common traps

• Dividing ₹1,040 by all 200 flowers, which gives ₹5.20 and ignores the 20 that cannot be sold.
• Charging the 30% profit on the cost of the 180 sellable flowers only (₹720 × 1.3 = ₹936), which also gives ₹5.20: the ₹800 was spent on all 200.

No directly related past PYQ was found.