Question

In a class of 7, there are 3 students who have done their homework.
If the teacher chooses 3 students, what is the probability that none of the three of them have done their homework?

Answer 1

♦Given:-

Total no. of Outcomes=7

Students who did their homework=3

Students who didnt do their homework=7-3=4

$\rule{200}{1}$

♦To Find:-

Probability of no. of students who haven't done their homework?

$\rule{200}{1}$

♦Proof:-

→Using the Formula,

→P(e)=$\frac{No. \ of \ outcomes}{Total \ no. \ of \ Outcomes}$

→P(students who havent done homework)=$\frac{Students \ who \ haven't \ done \ homework}{Total \ no. \ of \ Students}$

→P(e)=$\frac{4}{7}$=0.57%

$\rule{200}{5}$

Answer 2

Answer:

Step-by-step explanation:

Given -

Total number of outcomes = 7

Students who did their homework = 3

Students who did not done their homework = 7 - 3 = 4

Solution -

We know that, P(e) = Number of outcomes/Total number of outcomes

P(Students not done their homework) = Students who did their

homework/Total number of students

P(Students not done their homework) = 4/7

P(Students not done their homework) = 0.57 %

Thus, the probability that none of the three of them have done their homework is 0.57 %.