Given: 30 liters of a certain drink is to be divided between the students of \(5^{th}\) and \(10^{th}\) class. A school teacher is appointed on that duty. He gave \(\frac{3}{7}\) liter drink to each of \(5^{th}\) class student and then the remaining drink with \(\frac{3}{2}\) liters to each of \(10^{th}\) class student.
Asked: If there are 21 students of \(5^{th}\) class, then what will be the number of students of \(10^{th}\) class and what will be the percentage to the total number of students ?
There are 21 students of \(5^{th}\) class
30 liters of a certain drink is to be divided between the students of 5th and 10th class. A school teacher is appointed on that duty. He gave \(\frac{3}{7}\) liter drink to each of 5th class student and then the remaining drink with \(\frac{3}{2}\) liters to each of 10th class student.
Let students of 10th class be x
\(21 *\frac{ 3}{ 7} + x * \frac{3}{2} = 30\)
\(9 + \frac{3x}{2} = 30\)
\(x = 21*\frac{2}{3} = 14\)
Percentage to total number of students = \(\frac{14}{(21+14)} *100% = \frac{1400}{35} % = 40%\)
IMO B