Profit and Loss — A calculator is bought for ₹ 350 and sold at a gain of 15%. Compute the Selling Price (SP) of the calculator, showing the direct percentage-increase step on CP.

Introduction / Context:
This is a direct percentage-increase application: when an article is sold at a stated profit, SP is CP increased by that percentage. It assesses speed and accuracy with simple percent calculations.

Given Data / Assumptions:

• CP = ₹ 350
• Gain% = 15%

Concept / Approach:
For a profit of p%, SP = (1 + p/100) * CP. Substitute CP and p to find SP in one step.

Step-by-Step Solution:

Verification / Alternative check:
Profit amount = 402.50 − 350 = ₹ 52.50. Check percent: 52.50/350 * 100 = 15%, which matches exactly.

Why Other Options Are Wrong:
₹ 358 and ₹ 375 reflect smaller increases (≤ 7.14%). ₹ 472 and ₹ 415 overshoot the required 15% increase on ₹ 350.

Common Pitfalls:
Adding 15% of a wrong base (e.g., on an incorrect CP) or rounding too early. Always compute on the given CP.

Final Answer:
₹ 402.50