Riya and Sita started a business by investing Rs. ‘x’ and Rs. (x + 4,000), respectively. Four months later, Karan joined them by investing Rs. 12,000. If at the end of the year, the profit earned by Sita was 20% less than the profit earned by Riya and Karan together, then find the amount invested by Sita.

ATQ, Ratio of profit shares of Riya, Sita and Karan at the end of the year = (12 × x) : {12 × (x + 4000)} : (12000 × 8) So, 12x : 12(x + 4000) : 96000 Dividing the whole ratio by 12, we get: x : (x + 4000) : 8000 ATQ: Sita’s profit was 20% less than the profit of Riya and Karan together. So, Sita’s share = 80% of (Riya’s share + Karan’s share) (8000 + x) × 0.8 = (x + 4000) Or, 0.8x + 6400 = x + 4000 Or, 6400 − 4000 = x − 0.8x Or, 2400 = 0.2x So, x = 2400 / 0.2 = 12000 So, amount invested by Sita = x + 4000 = 12000 + 4000 = Rs. 16,000