An article priced at ₹ 100 undergoes a 10% increase and then another 10% increase. By how much has the price increased in total (in ₹)?

Introduction / Context:
Successive percentage changes compound multiplicatively. Two increases of 10% each do not simply add to 20%; the second 10% applies to the already increased amount.

Given Data / Assumptions:

• Initial price = ₹ 100.
• Increase 1: +10%.
• Increase 2: +10% again.

Concept / Approach:
After one 10% increase, multiply by 1.10. Apply the second 10% increase by multiplying by 1.10 again. Subtract the original to get the total absolute increase.

Step-by-Step Solution:
After first increase: 100 * 1.10 = 110After second increase: 110 * 1.10 = 121Total increase = 121 − 100 = 21

Verification / Alternative check:
Equivalent single multiplier = 1.10 * 1.10 = 1.21, which is a 21% increase on ₹ 100, i.e., ₹ 21.

Why Other Options Are Wrong:
20 ignores compounding; 110 and 121 are prices, not increases; 19 is arbitrary.

Common Pitfalls:
Adding percentages linearly for successive changes; percentages compound unless specified otherwise.

Final Answer:
21