A man travels 404 kilometres in partly by rail and steamer. He spends 10 hours more time on steamer. If the speed of the steamer is 30 km/hr and the velocity of rail is 50 km/hr, how much distance does he cover by steamer?
The disease that has been eradicated from the world is small pox. Smallpox was an infectious disease caused by one of two virus variants, Variola major and Variola minor. The last naturally occurring case was diagnosed in October 1977 and the World Health Organization (WHO) certified the global eradication of the disease in 1980.
In a class of 100 students, the average weight is 30 kg. If the average weight of the girls is 24 kg and that of the boys is 32 kg, then what is the number of girls in the class?