sandy wrote:
Set X consists of all the even integers from 1 to 100, inclusive, and set Y consists of all the integers divisible by 5 from 1 to 100,
exclusive. How many members of set X are not members of set Y?
Drill 3
Question: 5
Page: 290
There are 100 integers from 1 to 100.
HALF of them are even and HALF are odd.
So, there are
50 even integers in set X.
How many of those
50 even integers are ALSO in set Y?
Well, to be in BOTH set X AND set y, a number must be even AND a multiple of 5
Those numbers are 10, 20, 30, 40, 50, 60, 70, 80 and 90 (a total of
9 values)
Aside: We don't include 100 in this group, because we're told that set Y consists of all the integers divisible by 5 from 1 to 100,
exclusive How many members of set X are not members of set Y?Answer:
50 -
9 = 41
Answer: