lisa, mia, nina.......ratio of 6:4:7...added = 17....so lisa has 6/17 of the total dolls....mia has 4/17 of the total dolls and Nina has 7/17 of the total dolls.
Nina has 21 dolls.....she also has 7/17 of the total dolls... 7/17x = 21....with x being the total number of dolls x = 21 / (7/17) x = 21 * 17/7 x = 357/7 x = 51...so there are 51 total dolls
Lisa : she has 6/17 of the total dolls 6/17 * 51 = 306/17 = 18 dolls <====
Mia : she has 4/17 of the total dolls 4/17 * 51 = 204/17 = 12
so in summary, Nina has 21 dolls, Lisa has 18 dolls and Mia has 12 dolls for a total of 51 dolls
