Question

In o Class of 100 students, if any student opts Science,
then he/she can take any stream, medical or non-
medicol. 20 students took the non-medical stream, 20
students took medical stream. And 10 students took
both medical and non-medical streams. If a student is
selected at random, what is the probability that he/she
is a Science student?​

Answer 1

Answer:

1/2

Step-by-step explanation:

20+20+10=50

p(s)= 50/100

=2

Answer 2

The probability that he/she is a Science student is 3/10.

   Total number of students in the class =100

    ∴ n(S)=100

Let A be the event that students took the non- medical stream

∴ n(A)=20

∴ P(A)= $\frac{n(A)}{n(S)}$

∴ P(A)=$\frac{20}{100}$

Let B be the event that students took the medical stream

∴ n(B)=20

∴ P(B)= $\frac{n(B)}{n(S)}$

∴ P(B)=$\frac{20}{100}$

A∩B is the event when students took both non- medical stream and  medical stream

∴ n(A∩B)=10

∴ P(A∩B)= $\frac{10}{100}$

To find the probability that  he/ she is a science student

Formula

P(A∪B)=P(A)+P(B)−P(A∩B)

= $\frac{20}{100} + \frac{20}{100} - \frac{10}{100}$

= $\frac{20+20-10}{100}$

= $\frac{3}{10}$

Probability Definition

• Probability is a measure of the likelihood of an event to occur. Many events cannot be predicted with total certainty.

Formula for Probability

Probability of event to happen P(E) = Number of favorable outcomes/Total Number of outcomes.

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