某年级有200人,在考试中,1/8得优,1/3得良,5/12得及格,有多少人不及格?

200x(1-1/8-1/3-5/12) =200x(1-3/24-8/24-10/24) =200x(1-21/24) =200x3/24 =200/8 =25