Correct Answer - Option 1 : Rs.100
Given:
Let the initial investment of Q and R be Rs.a and Rs.4a respectively.
⇒ Total investment of Q = a × 6 + (a + 400) × 6 = Rs.(12a + 2400)
⇒ Total investment of R = 4a × 5 + (4a - 200) × 7 = Rs.(48a - 1400)
⇒ Profit share of R = 2100 - 1080 = Rs.1020
Then,
⇒ (12a + 2400)/(48a - 1400) = 1080/1020
⇒ (12a + 2400)/(48a - 1400) = 36/34
⇒ (12a + 2400)/(48a - 1400) = 18/17
⇒ a = 100
∴ Initial investment of Q = Rs.100.