Question

If a positive integer n is picked at random from the

positive integers less than or equal to 10, what is the 
probability that 5n + 3 ≤ 14?

Answer 1

It is a good practice to solve this inequality first:

`5\cdot n + 3 \leq 14`

`5\cdot n \leq 11`

`n \leq (11)/(5)`

`(11)/(5) = 2.2`
So we want to check, what is the probability, that this number is less than or equal to 2.2
Among 10 integers we have only 2 numbers that are less or equal to 2.2, namely 1 and 2. Therefore, the probability is:

`(2)/(10)=(1)/(5)`