Question

A number is chosen at random between 1 and 25 what is the probability that they number chosen is a square number or a factor of 8?

Answer 1

Number of square numbers under 25= 1, 4, 9, 16 and 25
= 5 numbers
number of factors of 8 under 25 = 8, 16 and 24
= 3 numbers
number of good outcomes = 5 + 3
= 8 good outcomes
total outcomes = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 and 25.
= 25 outcomes
probability = good outcomes ÷ total outcomes
= 8/25

The probability that they number chosen is a square number or a factor of 8 is 8/25.