Correct Answer - Option 2 : 3 : 1
Given:
Total money lent = Rs. 4000
Total interest received after 3 years = Rs. 1500
R1 = 10%
R2 = 20%
Calculation:
Let the money lent at 10% be x.
Money lent at 20% = 4000 – x
SI at 10% for 3 years = (x × 10 × 3)/100
⇒ 30x/100
SI at 20% for 3 years = (4000 – x) × 20 × 3/100
⇒ (240000 – 60x)/100
Total interest received after 3 years = Rs. 1500
30x/100 + (240000 – 60x)/100 = 1500
⇒ (240000 – 30x) = 150000
⇒ 30x = 90000
⇒ x = 3000
Sum of money lent at 20% = 4000 – 3000
⇒ 1000
Required Ratio = 3000 : 1000
⇒ 3 : 1
∴ The ratio of money lent at 10% to that at 20% is 3 : 1.