In a class of 60 students, the number of girls is one third the number of boys. Find the number of girls and boys in the class.
15 girls and 45 boys
Let girls = x, boys = 60 − x.x = (1/3)(60 − x) ⇒ 3x = 60 − x ⇒ 4x = 60 ⇒ x = 15, boys = 45.