# Master this section to score well

Published: Published Date - 11:34 PM, Fri - 10 June 22

**Hyderabad:** This article is in continuation to the last article on preparation for the Sub-Inspector of Police recruitment exam. Here are some practice questions and answers along with explanations on the Simple Interest and Compound Interest topic.

**1. If Rs 5,800 are divided into two parts, such that the simple interest obtained on the first part at the rate of 7% p.a. for a period of two years is equal to the simple interest earned on the second part at the rate of 5% for the period of three years, what is the first part?**

A. Rs 1400 B. Rs 2800 C. Rs 3000 D. Rs 3200

Ans: C

**Explanation:**

Let the amount 5800 divided into X, (5800-X)

As given the S.I are equal then,

X× 7/100 ×2= (5800-X) × 5/100 ×3

14X/100= 5800 x 15) /100 – 15x

29X=5800×15

X=3000

**2. At simple interest, a sum amounts to Rs 3360 in 6 years and to Rs 3400 in 7 years. What does it amount to in 9 years?**

A. 3600 B. 3500 C. 3480 D. 3450

Ans: C

**Explanation:**

Difference between the amounts in one year= 3400-3360= 40

Therefore Interest in 1 year= Rs. 40

Amount in 7th year=3400

Amount in 9th year= 3400 interest in two years

= 3400 80=Rs 3480

**3. The sum of money doubles itself at simple interest in 10 years. The number of years it would triple itself is**

A. 25 yrs B. 15 yrs C. 20 yrs D. 22 yrs

Ans: C

**Explanation:**

Given that sum of money doubles itself in 10 years

Therefore, Rate of interest = 10/100 x 100 = 10%

So the sum of money triple itself after the interest becomes 200%

No. of years=200/10= 20 years

**4. The present worth of Rs 169 due in 2 years at 4% per annum compound interest is**

A. Rs 150.50 B. Rs 154.75 C. Rs 156.25 D Rs.158

Ans: C

**Explanation:**

Amount A= P (1 R/100)t

169=p (1 4/100) 2 = p (26/25)2

P= 169× 625/ 676 = 156.25

**5. The CI on Rs 4000 for 6 months at 12% p.a. compounded quarterly is**

A. Rs 243.60 B. Rs 240 C. Rs 243 D Rs 243.50

Ans: A

**Explanation:**

Let P = Principal, R = Rate of Interest per annum, Time = T in years,

Amount = A and

If the interest is compounded quarterly then A = P(1 R/4 /100)4t

Here p=4000, R= 12%, T=1/2

A = 4000(1 3/100 ) 4× (1/2) = 4000× (103/100)2=

4000× 103×103/100x 100 =4243.6

Interest= amount- principal= 4243.6-4000=Rs 243.6

**6. What would be the compound interest on Rs.80,000 for a period of two years at the rate of 20% p.a. compounded six monthly?**

A. Rs 37,128 B. Rs 40,000 C. Rs 35,000 D. Rs 31,728

Ans: A

**Explanation:**

A = P (1 R/100 )t

P=80000, t=2, R=20%

Amount= 80000(1 10/100 ) 4

80000(11/10)4= 80000× 11/10 x 11/10 x 11/10 x 11/10 =117128

Interest= amount- principal=117128-80000=Rs 37128

**To be continued…**

**By Banda Ravipal Reddy**

**Director, SIGMA**

**Sai Institute of General Mental Ability**

**Hyderabad**