Saved Bookmarks
| 1. |
If the difference between CI &SI on a certain sum of money for 3 years at 10% p.a. is Rs. 93, find the sum (in Rs) |
|
Answer» • Rate(r) = 10% • Time(t) = 3 years • Difference = Rs 93 To Find : • The sum Solution :LET the sum be Rs P Find the Simple Interest First ★ S.I. = P × R × T/100 → S.I. = P × 10 × 3/100 → S.I. = Rs 3/10 P.... i) Find the COMPOUND Interest now : ★ C.I. = P [(1 + R/100)ⁿ - 1] → C.I. = P [(1 + 10/100)³ - 1] → C.I. = P [(11/10)³ - 1] → C.I. = P (11³ - 10³/10³) → C.I. = P (1331 - 1000/1331) → C.I. = Rs 331/1000 P....ii) As given, C.I. - S.I. = Rs 93 → Rs 331 P/1000 - Rs 3/10 P = RS 93 → Rs (331-300/1000) P = Rs 93 → Rs 31/1000 P = Rs 93→ P = Rs 93 × 1000/31 → P = Rs 3000 The required sum is Rs 3000. |
|