hi i am stuydiyng for a gre exam and i am having trouble figuring out a fraction/ratio problem. it states:

Mary has 11N marbles and cathy has 7N marbles so we have a ratio of 11:7. after the gift, Mary will have 11N - 3 marbles. after receiving 3 marbles , cathy will have 7N + 3 marbles. the new ration in terms of N, after the gift is: (11N -3)/(7N + 3) and the numerical value of this ratio is 16/11. How do we get 16/11 from (11N -3)/ (7N +3)