CA Foundation · Quantitative Aptitude · Equations
Ravi invests ₹x at a simple interest rate of 6% per annum and ₹(10,000 − x) at 8% per annum. His total annual interest is ₹700. What is the value of x?
Ravi invested ₹5,000 at 6% interest. Setting up the equation 0.06x + 0.08(10,000 − x) = 700 and solving yields x = 5,000.
- A₹5,000Correct
- B₹4,000
- C₹6,000
- D₹7,500
Explanation
Simple interest = P × R × T / 100. For the first investment: (x × 6 × 1) / 100 = 0.06x. For the second: ((10,000 − x) × 8 × 1) / 100 = 0.08(10,000 − x). Total: 0.06x + 0.08(10,000 − x) = 700. Simplifying: 0.06x + 800 − 0.08x = 700, so −0.02x = −100, giving x = 5,000.
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