Simple and Compound Interest Questions

Multiple choice
  1. $10\%$
  2. $8\%$
  3. $5\%$
  4. $4\%$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For 2 years, SI = 2 * (P * R / 100) = 400, so P * R / 100 = 200. CI = P * (1 + R/100)^2 - P = 410. Substituting P*R/100 = 200 into the CI formula: 200 + P * (R/100)^2 = 410, so P * (R/100)^2 = 210. Dividing the two equations: (P * R^2 / 10000) / (P * R / 100) = 210 / 200, so R/100 = 1.05, R = 5%.

Multiple choice
  1. I only

  2. I and II only

  3. II and III only

  4. I and III only

  5. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statement I: SI = 2000 for 5 years at 5000 principal means SI = 400 per year. Rate = (400/5000)*100 = 8%. With rate and principal, CI for 2 years can be calculated. Statement II: CI and SI are same for 1 year, which is always true for any rate, so it provides no info. Statement III: Amount > double in 10 years gives a range for the rate, but not a specific value. Thus, only I is sufficient.