Correct Answer - Option 4 : 50 ∶ 17

**Given:**

Amount Karan had = 7 × 5/7 = 5 lakhs

Amount Arjun had = 7 × 2/7 = 2 lakhs

Rate of interest = 5%

**Formula:**

Let P = Principle, R = rate of interest and N = time period

Simple interest = PNR/100

**Calculation:**

Time period for which Karan invested = 10 years

Time period for which Arjun invested = 10 - 18/12 = 17/2

Simple interest Karan will get = 5 × 10 × 5/100 = Rs.2.5 lakhs

Simple interest Arjun get = 2 × 17/2 × 5/100 = Rs.0.85 lakhs

**∴ Required ratio = 2.5 : 0.85 = 50 : 17**