454
Q:

# A problem is given to three students whose chances of solving it are 1/2, 1/3 and 1/4 respectively. What is the probability that the problem will be solved?

 A) 1/4 B) 1/2 C) 3/4 D) 7/12

Explanation:

Let A, B, C be the respective events of solving the problem and  be the respective events of not solving the problem. Then A, B, C are independent event

are independent events

Now,  P(A) = 1/2 , P(B) = 1/3 and P(C)=1/4

$∴$ P( none  solves the problem) = P(not A) and (not B) and (not C)

= $PA∩B∩C$

= $PAPBPC$

=  $12×23×34$

= $14$

Hence, P(the problem will be solved) = 1 - P(none solves the problem)

= $1-14$= 3/4

Q:

If the difference between the mode and median is 2, then the difference between the median and mean is:

 A) 2 B) 1 C) 3 D) 4

Explanation:

5 499
Q:

In a bag which contains 40 balls, there are 18 red balls and some green and blue balls. If two balls are picked up from the bag without replacement, then the probability of the first ball being red and second being green is 3/26. Find the number of blue balls in the bag.

 A) 16 B) 12 C) 10 D) 14

Explanation:

Total balls = 40

Red balls = 18

Let green balls are x

Then, (18/40) × (

15 781
Q:

A five digit number is formed with the digits 0,1,2,3 and 4 without repetition. Find the chance that the number is divisible by 5.

 A) 3/5 B) 1/5 C) 2/5 D) 4/5

Explanation:
5 digit number = 5! = 120
Divisible by 5 then the last digit should be 0
Then the remaining position have the possibility = 4!
= 24

10 533
Q:

In a single throw with 2 dices, what is probability of neither getting an even number on one and nor a multiple of 3 on other?

 A) 11/36 B) 25/36 C) 5/6 D) 1/6

Explanation:

We first calculate the probability of getting an even number on one and a multiple of 3 on other,Here, n(s) = 6x6 = 36 and

E = (2,3) (2,6) (4,3) (4,6) (6,3) (6,6) (3,2) (3,4)(3,6) (6,2)(6,4)

n(E) = 11P(E) = 11/36Required probability = 1-11/36 = 25/36

7 431
Q:

A bag contains 2 red Roses, 4 yellow Roses and 6 pink Roses. Two roses are drawn at random. What is the probability that they are not of same color?

 A) 1/6 B) 2/3 C) 14/33 D) 5/6

Explanation:

Possible outcomes = (RY, YP, PR)

2C1 4C1 + 4C1 6C1 + 6C1 2C1

Required probability = (2C1 4C1 + 4C1 6C1 + 6C1 2C1)/(12C2)

= 8 + 24 + 12/66

= 44/66

= 2/3.

45 2867
Q:

What is the probability that a number is divisible by 4?

 A) 2 B) 1/2 C) 1/4 D) 1

Explanation:

Probability is Number of favourable outcomes by total outcomes

Total comes = 2 (Divisible or not)

Favourable = 1 (Divisible)

Hence, probability = 1/2.

26 1738
Q:

The probability that z lies between 0 and 3.01

 A) 0.4987 B) 0.5 C) 0.9987 D) 0.1217

Explanation:

Probability between z = 0 and z = 3.01 is given by

P(0<z<3.01) = P(z<3.01) - P(z<0)

Reading from the z-table, we have

P(z<0) = 0.5

P(z<3.01) = 0.9987

Hence, P(0<z<3.01) = 0.9987 - 0.5 = 0.4987.

27 3420
Q:

There are 26 balls marked with alphabetical order A to Z. What is the probability of selecting vowels listed balls?

 A) 1 B) 21/26 C) 5/26 D) 5

Explanation:

We know that,

Total number of balls n(S) = 26

Number of vowels n(E) = 5

Hence, required probability = n(E)/n(S) = 5/26.