A committee of four students will be selected from a list that contains six Grade 9 students and eight Grade 10 students. What is the expected number of Grade 10 students on the committee?
2007-05-18 07:50:06 · 3 answers · asked by thomasgraham880 1 in Science & Mathematics ➔ Mathematics
there are 14 students to pick from
6 GradeNine students and 8 GradeTen
there is a 6/14 chance of picking a GradeNine student
there is a 8/14 chance of picking a GradeTen student
I will pick 4
(6 / 14) * 4 = 1.71428571 Grade nine
(8 / 14) * 4 = 2.28571429 Grade ten
2007-05-18 07:56:35 · answer #1 · answered by DanE 7 · 0⤊ 0⤋
x= number of Grade 10 students
4-x = number of grade 9 students
x/(4-x) =8/6 =4/3
4(4-x) = 3x
16-4x =3x
16=7x
x= 2.28
4-x = 1.72
So there should be 2 from each grade level
2007-05-18 15:08:21 · answer #2 · answered by ironduke8159 7 · 0⤊ 0⤋
only one, expect the least
2007-05-18 14:58:46 · answer #3 · answered by romel b 1 · 0⤊ 2⤋