SSC CPO 23 Nov 2020 Shift 1 Paper

One day, 90 students were travelling in a bus and the ratio of the number of boys to that of girls was 2 ∶ 1. The next day, the number of students remained the same, but the ratio of the number of boys to that of girls became 3 ∶ 2. What was the difference between the numbers of boys travelling in the bus on both the days?