A total sum of 36,000 is divided into two parts. One part is invested at 6% p.a. simple interest for 4 years and the other part is invested at 9% p.a. simple interest for 6 years. If the total simple interest received from both investments (after their respective periods) is 16,020, find the amounts invested at 6% and 9% respectively.
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Correct answer: B
Explanation
Given:
Total Amount = 36,000
First Part = 6% for 4 years
Second Part = 9% for 6 years
Total Interest = 16,020
According to the formula:
SI = (P × R × T) / 100
Let the amount at 6% be = x ⇒ Amount at 9% = (36,000 − x)
SI for the first part = x × 6 × 4 / 100 = 24x/100
SI for the second part = (36,000 − x) × 9 × 6 / 100 = 54(36,000 − x)/100
Total SI = 16,020
24x/100 + 54(36,000 − x)/100 = 16,020
24x + 54(36,000 − x) = 1,602,000
24x + 1,944,000 − 54x = 1,602,000
−30x = 1,602,000 − 1,944,000
−30x = −342,000
x = 11,400
Second Part = 36,000 − 11,400 = 24,600
Answer:
₹11,400 (at 6%) and ₹24,600 (at 9%)