A positive integer selected at random from the set of positive integers not…
2025
A positive integer selected at random from the set of positive integers not exceeding 200. Which of the followings is the probability that the selected number is divisible by either 2 or 5?
- A.
2/5
- B.
3/5
- C.
4/5
- D.
1/5
Attempted by 106 students.
Show answer & explanation
Correct answer: B
Answer: 3/5
Multiples of 2: There are 100 because 200 ÷ 2 = 100.
Multiples of 5: There are 40 because 200 ÷ 5 = 40.
Multiples of both 2 and 5 (multiples of 10): There are 20 because 200 ÷ 10 = 20.
Use inclusion–exclusion: 100 + 40 − 20 = 120 favorable numbers.
Probability: 120/200 = 3/5.
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