Subject: Maths-probability#1-2

Dear Sir/Mandom: Thankyour for your kindly help,i think the level of this question is secondary level as following:

1)There are 40,25,50 students in the traditional,reformed,and reformed traditional Calculas sections taught by three teachers. On one fine day the three sections congregate together to watch the NOVA video tape on Fermat's Last Theorem.

a) A student is randomly selected from he crowed of students.What is the expected number of students in the same section of this student?

****this question which i did not have any idea to do as follow for the part b
b) If one of the three teachers is selected at random, what is the expected number of students taught by is teacher?

James

Expected number or expected value is a term that statisticians use for mean or average. Thus the expected number of students taught by a teacher is the average number of students in the three classes.