there are 30 students in a classroom . the ratio of the # of girls to boys was 1 : 2 , how many boys are there ?
# of girls = x # of boys = 2 x x + 2 x = 30 3 x = 30 x = 30 / 3 = 10 boys = 2 x = 2 * 10 = 20 answer : c
multiply(divide(2, add(1, 2)), 30)