The difference between the S.I. and C.I. on a certain sum of money for

1.	The difference between the S.I. and C.I. on a certain sum of money for 2 years at 4% per annum is Rs. 20. Find the sum.
Answer» Given details are, Rate = 4 % per annum Time = 2years Compound Interest (CI) – Simple Interest (SI)= Rs 20 By using the formula, CI – SI = 20 P [(1 + R/100)ⁿ – 1] – (PTR)/100 = 20 P [(1 + 4/100)² – 1] – (P(2)(4))/100 = 20 P[51/625] – (2P)/25 = 20 51/625P – 2/25P = 20 (51P-50P)/625 = 20 P = 20 × 625 P = 20/7.918 = 12500 ∴ The sum is Rs 12500.

The difference between the S.I. and C.I. on a certain sum of money for 2 years at 4% per annum is Rs. 20. Find the sum.

Answer»

Given details are,

Rate = 4 % per annum

Time = 2years

Compound Interest (CI) – Simple Interest (SI)= Rs 20

By using the formula,

CI – SI = 20

P [(1 + R/100)ⁿ – 1] – (PTR)/100 = 20

P [(1 + 4/100)² – 1] – (P(2)(4))/100 = 20

P[51/625] – (2P)/25 = 20

51/625P – 2/25P = 20

(51P-50P)/625 = 20

P = 20 × 625

P = 20/7.918

= 12500

∴ The sum is Rs 12500.