In a school a seminar was held for two days for 8th class of 120 total students in which the number of boys to the number of girls was 3 : 2. Next day some students of class 7 also attended the seminar with the students of class 8th which increased the number of boys by 12 and the ratio of the boys to girls changed to 4 : 5. Then what is the number of girls of 7th who attended the seminar next day?