Certificates / Quantitative aptitude / Simple and Compound Interest
Simple and Compound Interest: lesson, then the certificate test
Step 1: the lesson (about 1 min)
Simple interest is the same every year; compound interest earns interest on interest.
- SI = P × R × T ÷ 100.
- CI amount = P × (1 + R/100)^T; CI = amount − P.
- For 2 years, CI − SI = P × (R/100)².
Worked example
₹5,000 for 2 years at 10% a year: what are SI and CI?
- SI = 5,000 × 10 × 2 ÷ 100 = 1,000
- Amount = 5,000 × 1.1 × 1.1 = 6,050, so CI = 1,050
- Check: CI − SI = 5,000 × 0.01 = 50
Answer: SI ₹1,000; CI ₹1,050
Watch out
- Half-yearly compounding: halve the rate and double the number of periods.
Made by Shishya (AI-assisted): a general method in our own words, with our own example; no exam or platform question is copied.
Step 2: the test
- 15 questions from Shishya's checked question bank, 20 minutes. Pass mark: 11 correct.
- Scored on Shishya's server; the answers are not shown afterwards, so the test stays fair. Each attempt draws new questions.
- Free. Your first test needs no account; sign up free to take more. Your answers and score are not stored; if you pass, you choose the name to print (ages 13 and up).
- It is a Shishya completion certificate — not a university or government credential. The test is not supervised.