The average of the ages of Sonu, Hari and Govind is 30 years. If their ages are in the ratio of 4 : 5 : 6, respectively, then the difference between the ages of Sonu and Govind is:

12 years

Sum of ages of Sonu, Hari and Govind = 30 × 3 = 90 years

Ratio of ages of Sonu, Hari and Govind = 4 : 5 : 6

ATQ,

4R + 5R + 6R = 90

15R = 90

1R = 6

Difference b/w age of Sonu & Govind = 2R = 2 × 6 = 12 years