If simple interest on a certain sum for 2 years is Rs 42 and compound interest is Rs 51 at the same rate, then what is the principal?
SI for 1 year = 42/2 = Rs 21. Difference between CI and SI for 2 years = 51 - 42 = Rs 9. Rate = (9 / 21) * 100% = 300/7%. Principal P = SI_1 / R% = 21 / (3/7) = Rs 49.
Correct Answer: Option B.
On a certain sum, simple interest for 2 years is Rs 9,600 whereas compound interest compounded annually is Rs 10,176. What is the rate of interest per annum?
SI for 1 year = 9600/2 = Rs 4800. CI - SI for 2 years = 10176 - 9600 = Rs 576. Rate R = (576 / 4800) * 100% = 12%.
Correct Answer: Option B.
What is the rate of interest (in %) if simple interest earned on a certain sum for 5 years is Rs 45,000 and compound interest earned for 2 years is Rs 18,630?
SI per year = 45000 / 5 = Rs 9,000. SI for 2 years = Rs 18,000. CI for 2 years = Rs 18,630. Difference for 2 years = 18630 - 18000 = Rs 630. Rate R = (630 / 9000) * 100% = 7%.
Correct Answer: Option B.
The compound interest and simple interest for two years on a certain sum of money at a certain rate of interest are Rs 2,257.50 and Rs 2,100 respectively. Find the principal and rate percent.
SI for 1 year = 2100 / 2 = Rs 1050. CI - SI for 2 years = 2257.50 - 2100 = Rs 157.50. Rate R = (157.50 / 1050) * 100% = 15%. Principal P = SI_1 / R% = 1050 / 0.15 = Rs 7,000.
Correct Answer: Option D.
The compound interest on a certain sum of money for 1 year 146 days at 14.28% (1/7) per annum is Rs 408. Find the principal.
14.28% = 1/7. Time = 1 yr + 146/365 yr = 1 + 2/5 yrs. For year 1: interest = 1/7 * P. For remaining 2/5 year: interest rate = 1/7 * (2/5) = 2/35. Total CI factor = 1/7 + 1/7 * (2/35) + 2/35 = (35 + 2 + 14)/245 = 51/245. P * 51/245 = 408 => P = 408 * 245 / 51 = Rs 1,960.
Correct Answer: Option C.