Question

The probability of Sita, Gita and Mita passing a test is 60 %, 40 % and 20 % respectively. What is the probability that at Sita and Gita will pass the test and Mita will not?

Answer 1

Assuming no one's cheating and Sita, Gita, and Mita's scores are independent of each other, the probability of Sita passing (60%), Mita passing (40%), and Mita failing (80%), combine with the formula
 P(A and B and C) = P(A)* P(B) * P(C),
 so 0.6 * 0.4 * 0.8 = .192
 giving a 19.2% chance that Sita and Gita will pass and Mita will not.

Answer 2

Answer:

Given

Probability of passing the test by Sita = 60% = 60/100

Probability of passing the test by Gita = 40% = 40/100

Probability of passing the test by Mita = 20% = 20/100

Formula

Probability of not happening even A = 1 - Probability of  happening even A

Probability of happening A and B = Probability of happening A × Probability of happening B

Calculation

Probability of not passing the test by Mita = 1 - Probability of passing the test by Mita

= 1 - (20/100)

= 80/100

Now,

Probability that at Sita and Gita will pass the test and Mita will not = Probability of passing the test by

Sita × Probability of passing the test by Gita × Probability of not passing the test by Mita

= (60/100) × (40/100) × (80/100)

= 192/1000

= (192/10)%

= 19.2