PDF format of Q & A on Simple Interest(Q1-Q25)

Simple Interest — Q1–Q25 (Export Fixed)
Simple Interest — Questions 1–25 (Stepwise)

Q1. Find the simple interest on ₹6000 for 3 years at 5% p.a.

Formula: S.I. = (P × R × T) / 100

Substitution: (6000 × 5 × 3) / 100

Calculation: 6000 × 5 × 3 = 90000; 90000 ÷ 100 = 900

Final Answer: ₹900

Q2. What will be the simple interest on ₹4800 for 2½ years at 6% p.a.?

Formula: S.I. = (P × R × T) / 100

Substitution: (4800 × 6 × 5⁄2) / 100

Calculation: 4800 × 6 × 2.5 = 72000; 72000 ÷ 100 = 720

Final Answer: ₹720

Q3. Find the simple interest on ₹3500 for 4 years at 4½% p.a.

Formula: S.I. = (P × R × T) / 100

Substitution: (3500 × 9⁄2 × 4) / 100

Calculation: 3500 × 4 × 4.5 = 63000; 63000 ÷ 100 = 630

Final Answer: ₹630

Q4. Calculate the simple interest on ₹7200 for 3¾ years at 8% p.a.

Formula: S.I. = (P × R × T) / 100

Substitution: (7200 × 8 × 15⁄4) / 100

Calculation: 7200 × 8 × 3.75 = 216000; 216000 ÷ 100 = 2160

Final Answer: ₹2160

Q5. On what sum will the simple interest be ₹450 in 3 years at 5% p.a.?

Formula: P = (100 × S.I.) / (R × T)

Substitution: (100 × 450) / (5 × 3)

Calculation: 45000 ÷ 15 = 3000

Final Answer: ₹3000

Q6. At what rate will ₹2000 amount to ₹2600 in 3 years?

Formula: R = (100 × S.I.) / (P × T)

Substitution: S.I. = 2600 − 2000 = 600 ; R = (100 × 600)/(2000 × 3)

Calculation: 60000 ÷ 6000 = 10

Final Answer: 10% p.a.

Q7. Find the time required for ₹1200 to earn ₹288 as S.I. at 6% p.a.

Formula: T = (100 × S.I.) / (P × R)

Substitution: (100 × 288) / (1200 × 6)

Calculation: 28800 ÷ 7200 = 4

Final Answer: 4 years

Q8. The S.I. on ₹7500 at 4% p.a. for 2½ years is —

Formula: S.I. = (P × R × T) / 100

Substitution: (7500 × 4 × 5⁄2) / 100

Calculation: 7500 × 4 × 2.5 = 75000; 75000 ÷ 100 = 750

Final Answer: ₹750

Q9. What amount will ₹9000 become in 2⅔ years at 9% p.a.?

Formula: A = P + (P × R × T) / 100

Substitution: 9000 + (9000 × 9 × 8⁄3)/100

Calculation: 9000 + (9000 × 24)/100 = 9000 + 2160

Final Answer: ₹11160

Q10. The S.I. on a certain sum for 5 years at 6% p.a. is ₹1800. Find the sum.

Formula: P = (100 × S.I.) / (R × T)

Substitution: (100 × 1800) / (6 × 5)

Calculation: 180000 ÷ 30 = 6000

Final Answer: ₹6000

Q11. Find S.I. on ₹2500 at 8% for 9 months.

Formula: S.I. = (P × R × T)/100

Substitution: (2500 × 8 × 3⁄4)/100

Calculation: 2500 × 8 × 0.75 = 15000; 15000 ÷ 100 = 150

Final Answer: ₹150

Q12. Find the rate when ₹400 becomes ₹460 in 3 years.

Formula: R = (100 × S.I.)/(P × T)

Substitution: (100 × 60)/(400 × 3)

Calculation: 6000 ÷ 1200 = 5

Final Answer: 5% p.a.

Q13. What will ₹6400 amount to in 2½ years at 10%?

Formula: A = P + (P × R × T)/100

Substitution: 6400 + (6400 × 10 × 5⁄2)/100

Calculation: 6400 + (6400 × 25)/100 = 6400 + 1600

Final Answer: ₹8000

Q14. Find S.I. on ₹10000 at 4% p.a. for 1¾ years.

Formula: S.I. = (P × R × T)/100

Substitution: (10000 × 4 × 7⁄4)/100

Calculation: 10000 × 4 × 1.75 = 70000; 70000 ÷ 100 = 700

Final Answer: ₹700

Q15. If ₹5000 gives ₹1000 interest in 4 years, find the rate.

Formula: R = (100 × S.I.)/(P × T)

Substitution: (100 × 1000)/(5000 × 4)

Calculation: 100000 ÷ 20000 = 5

Final Answer: 5% p.a.

Q16. Find the S.I. on ₹8000 at 12% for 6 months.

Formula: S.I. = (P × R × T)/100

Substitution: (8000 × 12 × 1⁄2)/100

Calculation: 8000 × 12 × 0.5 = 48000; 48000 ÷ 100 = 480

Final Answer: ₹480

Q17. On what sum will the interest be ₹300 in 2 years at 6%?

Formula: P = (100 × S.I.)/(R × T)

Substitution: (100 × 300)/(6 × 2)

Calculation: 30000 ÷ 12 = 2500

Final Answer: ₹2500

Q18. Find time for ₹900 to earn ₹135 at 5% p.a.

Formula: T = (100 × S.I.)/(P × R)

Substitution: (100 × 135)/(900 × 5)

Calculation: 13500 ÷ 4500 = 3

Final Answer: 3 years

Q19. S.I. on ₹1500 at 4% for 2¾ years.

Formula: S.I. = (P × R × T)/100

Substitution: (1500 × 4 × 11⁄4)/100

Calculation: 1500 × 4 × 2.75 = 16500; 16500 ÷ 100 = 165

Final Answer: ₹165

Q20. Find S.I. on ₹12000 at 7% for 1½ years.

Formula: S.I. = (P × R × T)/100

Substitution: (12000 × 7 × 3⁄2)/100

Calculation: 12000 × 7 × 1.5 = 126000; 126000 ÷ 100 = 1260

Final Answer: ₹1260

Q21. Find the amount for ₹8000 in 2 years at 5% p.a.

Formula: A = P + (P × R × T)/100

Substitution: 8000 + (8000 × 5 × 2)/100

Calculation: 8000 + 800 = 8800

Final Answer: ₹8800

Q22. S.I. on ₹5000 for 8 months at 9% p.a.

Formula: S.I. = (P × R × T)/100

Substitution: (5000 × 9 × 2⁄3)/100

Calculation: 5000 × 9 × 0.666... = 30000; 30000 ÷ 100 = 300

Final Answer: ₹300

Q23. Find rate if ₹7000 becomes ₹7630 in 3 years.

Formula: R = (100 × S.I.)/(P × T)

Substitution: S.I. = 7630 − 7000 = 630 ; (100 × 630)/(7000 × 3)

Calculation: 63000 ÷ 21000 = 3

Final Answer: 3% p.a.

Q24. What sum will earn ₹450 at 9% in 2½ years?

Formula: P = (100 × S.I.)/(R × T)

Substitution: (100 × 450)/(9 × 5⁄2)

Calculation: = 45000 ÷ 22.5 = 2000

Final Answer: ₹2000

Q25. Find S.I. on ₹10000 at 3¾% for 4 years.

Formula: S.I. = (P × R × T)/100

Substitution: (10000 × 15⁄4 × 4)/100

Calculation: = (10000 × 15) ÷ 100 = 1500

Final Answer: ₹1500

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