ICSE Class 10 Mathematics: Compound Interest — Important Questions with Answers 2026

Short Answer Questions (2-3 Marks)

• Q: A sum of ₹10,000 is invested at 10% p.a. compounded annually for 3 years. Find the compound interest.
  Ans: Using A = P(1 + r/100)ⁿ: A = 10000(1 + 10/100)³ = 10000 × (1.1)³ = 10000 × 1.331 = ₹13,310. CI = A - P = 13310 - 10000 = ₹3,310.
• Q: Find the difference between CI and SI on ₹8,000 at 5% p.a. for 2 years.
  Ans: SI = Prt/100 = 8000 × 5 × 2/100 = ₹800. CI: A = 8000(1.05)² = 8000 × 1.1025 = ₹8,820. CI = 8820 - 8000 = ₹820. Difference = CI - SI = 820 - 800 = ₹20. Shortcut: Diff = P(r/100)² = 8000 × (0.05)² = ₹20.
• Q: At what rate percent p.a. will ₹5,000 amount to ₹6,050 in 2 years compounded annually?
  Ans: A = P(1 + r/100)ⁿ. 6050 = 5000(1 + r/100)². (1 + r/100)² = 6050/5000 = 1.21. 1 + r/100 = √1.21 = 1.1. r/100 = 0.1. r = 10% p.a.

Exam Tips for This Chapter

• Revise all definitions and laws from Compound Interest — they are commonly asked as 1-2 mark questions
• Practice diagrams related to Compound Interest — neat labelled diagrams carry 2-3 marks
• For numericals, always show formula → substitution → answer with correct units
• Previous year analysis shows Compound Interest carries 8-12 marks in the board exam