Solve the following mathematical problems:
In a boys school, if 5 students sit in every bench, 4 benches are empty. But if 3 students sit in every bench. 20 students are left standing. What is the number of benches in the class?
(Equation)Let, number of total bench is x
∴Number of students = 5x - (4 5) = 5x - 20
In second case, number of students will bc = 3x + 20
According to the question,
5x - 20 = 3x + 20
= 5x - 3x = 20 + 20
= 2x = 40
Number of benches is 20.