Probability - Online Test

Q1. A dice is rolled 6 times. The probability of obtaining 2 and 4 exactly three times each is
Answer : Option D
Explaination / Solution:

Total ways of getting 2 and 4 exactly 3 times is 6! / (3! 3!) = 20

Total number of ways in throwing 6 dice is 66

Therefore probability is 20/ 66 = 5/11664


Q2. A dice has 3 faces each bearing ‘ 2 ‘ and three faces each bearing ‘ 6 ‘. It is rolled once. The probability of showing up ‘a six ‘ is
Answer : Option D
Explaination / Solution:

Total no. of outcomes = 6={2,2,2,6,6,6}

p(getting a six)=3/6=1/2


Q3. The total area under the standard normal curve is
Answer : Option D
Explaination / Solution:
No Explaination.


Q4. Neelam and Nidhi throw with a dice .The chance that both Neelam and Nidhi throw the same number is
Answer : Option A
Explaination / Solution:

TOTAL NO. OF OUTCOMES=62=36

no. of outcomes in which both throws same no.={(1,1),(2,2),(3,3),(4,4),(5,5),(6,6)}=6

p(both throws same no.)=6/36=1/6


Q5. A dice is tossed once and even number has come up. The chance that it is either 2 or 4 is
Answer : Option D
Explaination / Solution:

Total number of ways of getting even number is 3

Out of these 3 even number we have to get either 2 or 4 which can be done in 2 ways.

So required probability is 2/3


Q6. A pair of dice is tossed once and a total of 8 has come up. The chance that both the dice show up same number is
Answer : Option C
Explaination / Solution:

on tossing a pair of  dice total outcomes are 36

out of which getting a total of 8 have possiblities {(2,6),(6,2),(3,5),(5,3),(4,4)}=5

and from these 5 outcomes getting same no. on both dice is (4,4)=1

so, probability is 1/5


Q7. The probability of having atleast one head in 5 throws of a coin is
Answer : Option A
Explaination / Solution:
No Explaination.


Q8. A fair coin is tossed a fixed number of times. If the probability of getting 4 heads is equal to the probability of getting 7 heads, then the probability of getting 2 heads is
Answer : Option D
Explaination / Solution:
No Explaination.


Q9. From a pack of 52 cards, the cards are drawn one by one till an ace appears. The chance that an ace does not come up in first 26 cards is
Answer : Option A
Explaination / Solution:
No Explaination.


Q10. Three of the 6 vertices of a regular hexagon are chosen at random .The probability that the triangle with these vertices is equilateral is
Answer : Option A
Explaination / Solution:
No Explaination.