Problems on Simple Interest with Solutions for Competitive Exams

Simple Interest Problems with Solutions

Q.6. The difference between SI and CI compounded annually on a certain sum of money for 2 years at 8% per annum is Rs. 12.80. Find the principal.

(A) 1000

(B) 2000

(C) 3000

(D) 4000

SI = x * 2 * 8 / 100 = 4x/25

CI = x[1+ 8/100]2 – x → 104x/625

Therefore, 104x/625 – 4x/25 = 12.80

Solving which gives x, Principal = Rs. 2000.

Q.7. What percentage of simple interest per annum did Anand pay to Deepak?

I. Anand borrowed Rs. 8000 from Deepak for four years.

II. Anand returned Rs. 8800 to Deepak at the end of two years and settled the loan.

A. I alone sufficient while II alone not sufficient to answer

B. II alone sufficient while I alone not sufficient to answer

C. Either I or II alone sufficient to answer

D. Both I and II are not sufficient to answer

E. Both I and II are necessary to answer

I gives, P = Rs. 8000 and T = 4 years.

II gives, S.I. = Rs. (8800 - 8000) = Rs. 800.

⸫ R = [(100 x S.I.)/(P x T)]

= [(100 x 800)/(8000 x 4)]%          

= 2 1/2  % p.a.

Thus, I and II both are needed to get the answer

Q.8.  A certain principal amounts to Rs. 15000 in 2.5 years and to Rs. 16500 in 4 years at the same rate of interest. Find the rate of interest.

(A) 7%

(B) 6%

(C) 9%

(D) 8%

Simple interest for (4-2.5) years = 16500 – 15000

Therefore, SI for 1.5 years = Rs. 1500.

SI for 2.5 years = (1500/1.5) * 2.5 = 2500

Principal amount = 15000 – 2500 = Rs. 12500.

Rate of Interest = {(2500 * 100) / 12500} * 2.5 → R = 8%.

Q.9. A certain amount earns simple interest of Rs. 1750 after 7 years. Had the interest been 2% more, how much more interest would it have earned?

A. Rs. 35

B. Rs. 245

C. Rs. 350

D. Cannot be determined

E. None of these

Since the principal is not given, so data is inadequate

Q.10. Find the compound interest on Rs. 10000 at 12% rate of interest for 1 year, compounded half-yearly.

(A) 12360

(B) 1236

(C) 11236

(D) 10025

Therefore, CI = 11236 – 10000 = Rs. 1236

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