In a school, the boys and girls are in the ratio 9 : 5. If there are 425 girls, what is the total number of students in the school?

Arrange the following ratios in descending order of magnitudes :

(i) (5 : 6), (8 : 9), (13 : 18) and (19 : 24)

(ii) (6 : 7), (13 : 14), (19 : 21) and (23 : 28)

(iii) (7 : 12), (9 : 16), (13 : 20) and (5 : 8)

Arrange the following ratios in ascending order of magnitudes :

(i) (4 : 9), (6 : 11), (7 : 13) and (27 : 50)

(ii) (2 : 3), (8 : 15), (11 : 12) and (7 : 16)

(iii) (3 : 5), (4 : 9), (5 : 11) and (10 : 17)