Correct Answer - Option 3 : Rs. 3500

**Given:**

Compound interest for the 3rd year = Rs.

Rate of interest = 10%

**Concept used:**

Tree method

**Calculation:**

Let the principal be Rs. x

So, for 2nd and 3rd year principal be 2x and 3x

According to the question,

x/10

2x/10 x/100

3x/10 3x/100 x/1000

(3x/10 + 3x/100 + x/1000) = 1158.50

⇒ (300x + 30x + x)/1000 = 1158.50

⇒ 331x = 1158500

⇒ x = 3500

⇒ The principal = Rs. 3500

**∴ The sum he has deposited each year is Rs. 3500**