A number is selected at random from the numbers 1 to 30. What is the probability that it is divisible by either 3 or 7 ?

Question

নিচের অপশন গুলা দেখুন

• 1/30
• 1/25
• 2/30
• 1/2

Answer 1

সঠিক উত্তর হচ্ছে: op1/30

ব্যাখ্যা:

Let A be event of selecting a number divisible by 3. B be the event of selecting a number divisible by 7.

  

 A = { 3, 6, 9, 12, 15, 18, 21, 24, 27, 30 }, so n(A)=10
 B = { 7, 14, 21, 28 }, n(B)= 4 

 

Since A and B are not mutually exclusive So :