Correct Answer - Option 1 : 3 months

**Given **

Chaman starts a business = Rs. 30,000

Dheeraj investment = Rs. 40,000

**Formula Used **

Investment = capital × time

**Calculation **

Chaman investment for 12 months = 30000 × 12 = Rs. 360000

Dheeraj investment for x months = 40000 × x = 40000x

⇒ Profit Ratio = 1 : 1

⇒ investment ratio = 1 : 1

⇒ 360000 = 40000x

⇒ x = 9 months

⇒ Dheeraj invest the capital = 9 months

⇒ so Dheeraj join the business after = 12 - 9 = 3 months

**∴ Dheeraj invest the money after 3 months **