Unit conversion and target profit count A buys oranges at Rs 2 for 3 oranges and sells at Rs 1 per orange. How many oranges must be sold to make a profit of Rs 10?

Introduction / Context:
This problem converts a 'bulk price' to a per-unit cost and compares it with a per-unit selling price to find the required quantity for a target profit.

Given Data / Assumptions:

• CP: Rs 2 for 3 oranges ⇒ CP per orange = 2/3.
• SP per orange = Rs 1.
• Target profit = Rs 10.

Concept / Approach:
Profit per orange = SP − CP. Number of oranges needed = Target profit / Profit per orange.

Step-by-Step Solution:
CP per orange = 2/3 ≈ 0.6667.Profit per orange = 1 − 2/3 = 1/3 ≈ 0.3333.Required count = 10 / (1/3) = 30 oranges.

Verification / Alternative check:
Total revenue for 30 oranges = 30 × 1 = 30; total cost = 30 × 2/3 = 20; profit = 10 (matches target).

Why Other Options Are Wrong:
20 or 24 underachieve the target; 36 or 40 exceed the minimum needed.

Common Pitfalls:
Misreading 'Rs 2 for 3' as 'Rs 3 for 2' or computing profit percent instead of count.

Final Answer:
30 oranges