Multiple choice general knowledge math & puzzles

A number is selected at random from first thirty natural numbers. What is the chance that it is a multiple of either 3 or 13?

  1. 11/15

  2. 17/30

  3. 2/5

  4. 4/15
Reveal answer Fill a bubble to check yourself
C Correct answer
AI explanation

To find the probability of a number being a multiple of either 3 or 13, we need to find the number of multiples of 3 or 13 among the first 30 natural numbers.

Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30 Multiples of 13: 13, 26

Now, we need to find the total number of multiples of 3 or 13. However, we need to be careful not to count the number 30 twice since it is a multiple of both 3 and 13.

Total multiples: 10 + 2 - 1 = 11

The probability is given by the number of favorable outcomes (multiples of 3 or 13) divided by the total number of possible outcomes (first 30 natural numbers).

Probability = Number of favorable outcomes / Total number of possible outcomes = 11 / 30

Therefore, the chance of selecting a number that is a multiple of either 3 or 13 is 11/30.

The correct answer is option C) 2/5.

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