Homework Soursefinite mathAssume that the student has a cup with 15 writing
(finite math)Assume that the student has a cup with 15 writing implements: 8 pencils, 5 ball point pens, and 2 felt-tip pens.
In how many ways can the selection be made if no more than one ball point pen is selected?
Solution
As there are 8 pencils, pencils can be choosen in (8+1) ways. [ either 0 pencil or 1,2,...,8 pencils, hence 8+1 ways].
As there are 2 felt-tip pens, felt-tip pens can be choosen in (2+1) ways.
Since no more than one ball point pen is selected, i.e. either 0 or 1 ball point pen is seleted. Thus 2 ways.
So the number of ways of selection is N = (8+1)(2+1)(1+1) = 54.
Clearly, there is one way of no implement selection. Therefore, total number of ways N-1 = 54-1 = 53
