Simple and Compound Interest Questions

Multiple choice
  1. $Rs.\ 702$
  2. $Rs.\ 398$
  3. $Rs.\ 425$
  4. $Rs.\ 756$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let the parts be P1, P2, P3. Interest = P*R*T/100. 4*1*P1/100 = 4*2*P2/100 = 4*3*P3/100. P1 = 2P2 = 3P3. P1:P2:P3 = 6:3:2. Total parts = 11. Smallest part = (2/11) * 2189 = 2 * 199 = 398.

Multiple choice
  1. Only $I$
  2. Only $II$
  3. Either $I$ or $II$
  4. neither $I$ or $II$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement 1: CI-SI for 2 years = P(r/100)^2. With P=15000 and difference=170, r can be found. Statement 2: SI = P*r*t/100. With P=15000, SI=2500, t=2, r can be found. Both are sufficient independently.

Multiple choice
  1. $Rs.27800$
  2. $Rs.28100$
  3. $Rs.29100$
  4. $Rs.30000$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For simple interest, the half-yearly charging does not change the annual simple-interest calculation. For 42 months, or 3.5 years, interest is 20000 x 13/100 x 3.5 = Rs. 9100. The amount is Rs. 29100.

Multiple choice
  1. $3\dfrac {4}{9}\%$
  2. $2\dfrac {4}{9}\%$
  3. $5\dfrac {4}{9}\%$
  4. $4\dfrac {4}{9}\%$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The simple interest from Geeta is (600 * 2 * R) / 100 = 12R, and from Seeta is (150 * 4 * R) / 100 = 6R. The total interest received is 12R + 6R = 18R = 80, which gives R = 80 / 18 = 4 4/9%.

Multiple choice
  1. $300\ rupees$
  2. $1000\ rupees$
  3. $700\ rupees$
  4. $500\ rupees$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Simple interest is directly proportional to the principal amount when the rate and time are constant. If the principal is halved (from 3000 to 1500), the interest is also halved (from 600 to 300).