SOLUTION: An integer is chosen at random from the first 200 positive integers. If the integer chosen is even, find the probability that it is divisible by 5.

Algebra ->  Statistics  -> Binomial-probability -> SOLUTION: An integer is chosen at random from the first 200 positive integers. If the integer chosen is even, find the probability that it is divisible by 5.      Log On


   



Question 1135861: An integer is chosen at random from the first 200 positive integers. If the integer chosen is even, find the probability that it is divisible by 5.
Found 2 solutions by Alan3354, ikleyn:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
An integer is chosen at random from the first 200 positive integers. If the integer chosen is even, find the probability that it is divisible by 5.
2 & 5 --> divisible by 10
----------------
20 of 200 ---> 0.1

Answer by ikleyn(52793) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let N be the set of all integers from 1 to 200, inclusively.


Let E be the subset in N consisting of all even numbers. 
The number of elements in E is  200%2F2 = 100.


Let T be the subset in E, consisting of numbers of E divisible by 5.
It is clear that the set T consists of all integer numbers divisible by 10, and the number of elements in T is 20.


The problem asks : if the integer is randomly chosen from E, what is the probability that it belongs to T ?


Since the set T is the subset in E and has in five times less elements than E, the answer is  OBVIOUS :  this probability is  1%2F5.

Answered and solved.