A candy shop owner buys three kinds of candies: red, blue, and green. Red candies are purchased at 3 for ₹15, blue candies at 4 for ₹18, and green candies at 5 for ₹22. He mixes them in the ratio 1 : 1 : 2. He sells all the mixed candies at 2 for ₹10. What is his approximate gain or loss percentage?
- (a)Loss of 9.2%
- (b)Profit of 9.29%
- (c)Profit of 10%
- (d)Loss of 10%
Answer
Why
Correct — B. Price one candy of each kind, cost one 1 : 1 : 2 set, then compare it with what the set sells for.
Red = 15 ÷ 3 = ₹5 each
Blue = 18 ÷ 4 = ₹4.50 each
Green = 22 ÷ 5 = ₹4.40 each
Cost of 1 red + 1 blue + 2 green = 5 + 4.50 + 8.80 = ₹18.30
Sale of those 4 candies at 2 for ₹10 = ₹20
Profit = 20 − 18.30 = ₹1.70
Profit % = 1.70 ÷ 18.30 × 100 ≈ 9.29% → option (b)
Why the others are wrong
- (a)Loss of 9.2% — Wrong direction. No candy costs more than ₹5 and every candy sells for ₹5, so the mix cannot make a loss. The size is close to the real 9.29% gain.
- (c)Profit of 10% — A 10% profit would need the 4-candy set to cost 20 ÷ 1.1 ≈ ₹18.18. The 1 : 1 : 2 set costs ₹18.30, so the gain falls just short, at 9.29%.
- (d)Loss of 10% — Wrong on both counts. Selling at ₹5 against an average cost of ₹4.575 is a gain, and a 10% loss would need each candy to cost about ₹5.56, dearer than the dearest (red, ₹5).
Concept
Goods bought at different rates and mixed have one cost price: a weighted average of the unit prices, weighted by how many of each go in.
The 1 : 1 : 2 ratio counts green twice, so the average is 18.30 ÷ 4 = ₹4.575 a candy, not the plain average of ₹5, ₹4.50 and ₹4.40.
Profit % is measured on that cost price: (5 − 4.575) ÷ 4.575 × 100 ≈ 9.29%.
The options come in look-alike pairs: a loss of 9.2% beside a profit of 9.29%, a profit of 10% beside a loss of 10%. Decide the direction before the size.
Key facts
- Unit cost from a 'k for ₹N' rate = N ÷ k: 3 for ₹15 is ₹5 a candy.
- Mixture cost price = total cost ÷ total quantity: here ₹18.30 ÷ 4 = ₹4.575.
- Profit % = profit ÷ cost price × 100: 1.70 ÷ 18.30 × 100 ≈ 9.29%.
Study next
Common traps
- Taking the plain average of ₹5, ₹4.50 and ₹4.40 (about ₹4.63) ignores the 2 in the ratio and gives about 7.9%.
- Dividing the ₹1.70 profit by the ₹20 selling price gives 8.5%. Profit % is always on cost.
The same three-rate mix is on 14 Sep 2025, 12:30, Quant Q.15: mangoes at 4 for ₹10, 5 for ₹12 and 2 for ₹5, mixed 2 : 3 : 1, cost ₹14.70 for 6 and sell for ₹14, a loss of about 4.76%.
Notebooks mixed 3 : 4 : 3 and sold at 4 for ₹19 are on 15 Sep 2025, 16:00, Quant Q.11, where the gain works out to about 9.2%.
Related PYQs
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