Out of Rs. 15,000, 'X' invested a part of it on compound

Solution

ATQ,

Let the amount invested by 'X' on compound interest be Rs. ‘p’. Then, amount invested by 'X' on simple interest = Rs. (15,000 – p) Simple interest = Principal × Rate × Time ÷ 100 Simple interest earned = (15,000 – p) × 15 × 2 ÷ 100 = Rs. (4,500 – 0.3p) Compound interest = Principal × (1 + Rate ÷ 100)² – Principal Compound interest = p × (1.2)² – p ⇒ Compound interest = 1.44p – p = 0.44p ATQ: 0.44p + 4,500 – 0.3p = 5,760 ⇒ 0.14p = 1,260 ⇒ p = 9,000 Amount invested on simple interest = 15,000 – 9,000 = 6,000 Simple interest earned = 6,000 × 0.15 × 2 = Rs.1,800