Question 10 - Theory - Probability

Activity: Ask all the students in your class to write a 3-digit number. Choose any student from the room at random. What is the probability that the number written by her/him is divisible divisible by digits is  by 3? Remember that a number is divisible by 3, if the sum of its digits are divisible by 3

Note : This is an activity, so we assume some values and solve

Let's assume these values

Let number of Classmates be 20

And numbers written by them are

123, 374, 223, 911, 121, 363, 542, 413, 821, 736, 417, 163, 616, 637, 275, 615, 522, 314, 716, 946

So, Total numbers written = 20

Now, we know that

Number is divisible by 3 if its sum of digits are divisible by 3

Here,

Numbers divisible by 3 are: 123, 363, 417, 615, 522

Now,

We need to find Probability that number is divisible by 3

Probability that number is divisible by 3 = Number of numbers divisible by 3/ Total numbers

 = 5/20

 = 1/4