the capitals of 4 partners a,b,c,d are in the ratio of 7:8:6:5.a's and c's capitals are there in the business for the entire year.if each partner kept his money invested in the business for a period which is more than 6 months and b and d together get 111/267 of the total profit ,then for how many months is d's capital invested?pl. provide sol. also.

1) 11
2) 7
3) 9
4) cannot be determined