Correct Answer - B
Capital invested by A
(A द्वारा निवेशित राशि ) =रुपये 42,000
Capital invested by B ( द्वारा निवेशित राशि ) =रुपये 49,000
Ratio of profits of A and `B = 9000`
`:7000 = 9:7`
We know, `(C_(1) xx T_(1))/(C_(2)xxT_(2)) = (P_(1))/(P_(2))`
`(42,000 xx 12)/(49,000 xx T_(2)) = (9)/(7)`.
`T_(2) =8` months
It means B invested his capital for 8 months. It means he joined business after `(12 -8=4)` months. (अतः B ने चार महीने बाद व्यसाय में निवेश किया )