ECAT Mathematics Chapter 9 Permutation, Combination and Probability

A key ring is an example of

• Permutation A
• Circular permutation B
• Combination C
• None D

Product of any n consecutive positive integers is divisible by

• n A
• √n B
• n! C
• None D

If A and B are two disjoint events then

• P(A∪B)=P(A)+P(B) A
• P(A∪B)=P(A)-P(A∪B) B
• P(A∪B)=P(A)or P(B) C
• None D

20. 19. 18. 17= _______

• 
  A
• 
  B
• 
  C
• 
  D

A coin is tossed. If head comes up, a die is thrown but if tail comes up, the coin is tossed again. The probability of obtaining a head and an even number is

• 1/8 A
• 2/8 B
• 3/8 C
• None of these D

• 1.5 A
• 1.2 B
• 8 C
• None of these D

The number of words that can be formed out of the letters of the word ASSASSINATION is

• 
  A
• 
  B
• 
  C
• 
  D

The sum of all positive integral multiple of 5 less than 100 is

• 950 A
• 760 B
• 1230 C
• 875 D

A card is drawn from a pack of cards numbered 1 to 52, the probability that the number on the card is a perfect square is

• 1/13 A
• 2/13 B
• 7/52 C
• None of these D

The sample space for tossing a coin once is

• {T, T} A
• {H, H} B
• {H, T} C
• None of these D

The sample space for tossing a coin twice is

• {H, T} A
• {HH, HT, TH, TT} B
• {H, T, HH} C
• {HH, HT, TT} D

A machine operates if all of its three components function. The probability that the first component fails during the year is 0.14, the second component fails is 0.10 and the third component fails is 0.05. the probability that the machine will fail during the year is

• 0.2647 A
• 0.2692 B
• 0.3647 C
• None of these D

Two cards are drawn at random without replacement. the probability that the first is a king and second is not a king is

• 48 / 663 A
• 24 / 663 B
• 12 / 663 C
• None of these D

• 
  A
• 
  B
• 
  C
• 
  D

(n + 2) (n + 1)n in factorial form is

• 
  A
• 
  B
• 
  C
• 
  D

If two balls are drawn from a bag containing 3 white, 4 black and 5 red balls. Then the probability that the drawn balls are of different colours is

• 1 / 66 A
• 3 / 66 B
• 19 / 66 C
• 47 / 66 D

Arithmetic mean between 14 and 18 is

• 16 A
• 17 B
• 15 C
• 32 D

A die is thrown 100 times. If getting an odd number is considered a success, the variance of the number of successes is

• 50 A
• 25 B
• 10 C
• 100 D

9. 8. 7. 6= ______

• 
  A
• 
  B
• 
  C
• 
  D

Fifteen girls compete in a race. The first three places can be taken by them in

• 3! ways A
• 12! ways B
• 15 x 14 x 13 ways C
• 42 ways D

• 
  A
• 
  B
• 
  C
• 
  D

In a country 55% of the male population has houses in cities while 30% have houses both in cities and in villages find the percentage of the population that has houses only in villages

• 45 A
• 30 B
• 25 C
• 50 D

The factorial of a positive integers is a (an)

• Rational number A
• Positive integer B
• Real number C
• None D

Number of ways of writing the letters of WORD taken all at a time is

• 24 A
• 4 B
• 12 C
• 6 D

Number of combination of zero or more things out of n different things

• nPn A
• nPr B
• nCr C
• 2n D

Three dice are thrown together. The probability of getting a total of at least 6 is

• 103 / 108 A
• 10 / 216 B
• 93 / 108 C
• None of these D

The domain of a finite sequence is a

• Set of natural numbers A
• R B
• Subset of N C
• Proper subset of N D

Which one is not defined∀n∈Z+

• -n! A
• n! B
• (-n)! C
• n!+0!=n!+1 D

• 0 A
• -1 B
• 1 C
• 2 D

• 
  A
• 
  B
• 
  C
• 
  D