Question

There were 350 pupils in a hall and 20 percent of them were girls. Then 50 girls entered the hall. How many girls were there in the hall in the end?

Answer 1

Initially, there were 20/100 * 350 = <<20/100*350=70>>70 girls in the hall.
When 50 more girls entered, the total number of girls in the hall became 70 + 50 = <<70+50=120>>120. Answer: \boxed{120}.