A school contains students ingrades 1,2,3,4,5 and 6. Grades 2,3,4,5 and 6 all contain the samenumber of students, but there are twice this number in grade 1.
a)If a student is selected at random from a list of all thestudents in the school, what is the probability that he will be ingrade 3?
b)What is the probability that the selected student will be inan odd-numbered grade?