There are as many girls as there are boys in a class. 8 girls went for a dance competition. now there are twice as many boys as there are girls in the class. how many students were there in the class initially?

Let the number of girls be x and the number of boys be y

The number of boys is the same as the number of girls.
x = y 
The number of boys is twice the number of girls when 8 girls left.
2(x - 8) = y

x = y (1)
2(x - 8) = y (2)

Sub (1) into (2)

2(y - 8) = y
2y - 16 = y
2y - y = 16
y = 16
There were 16 boys and 16 girls initially.

16 + 16 = 32 
There were a total of 32 students in the class initially.