ECAT Pre General Science Mathematics Chapter 9 Permutation, Combination & Probability Online Test

A class contains nine boys and three girls, in how many ways can the teacher choose a committee of four?

• 60 A
• 460 B
• 495 C
• 272 D

• 8 A
• 1/56 B
• 56 C
• None of these D

• 
  A
• 
  B
• 
  C
• 
  D

• 5 A
• 10 B
• 20 C
• 30 D

Number of selections of n different things out of n

• 1 A
• nPr B
• n! C
• nPr D

The factorial of a positive integers is a (an)

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

A bag contains 5 white, 7 red and 5 black balls. If four balls are drawn one by one with replacement, the probability that none is white is

• (11/16)² A
• (5/16)² B
• (11/16)⁴ C
• (5/16)⁴ D

The domain of an infinite sequence is a

• Set of natural numbers A
• R B
• Subset of N C
• None of the above D

Two cards are drawn at random from a well shuffled pack of cards. The probability that at least one of them is a face card is

• 3 / 17 A
• 5 / 17 B
• 7 / 17 C
• 9 / 17 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

A sequence is a function whose domain is

• N A
• Subset of N B
• R 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

The value of n, when ⁿP₂= 20 is

• 3 A
• 4 B
• 6 C
• 5 D

• 
  A
• 
  B
• 
  C
• 
  D

The number of 5-digit number that can be formed from the digits 1,2,4,6,8, when 2 and 8 are never together is

• 72 A
• 48 B
• 144 C
• 20 D

• P(A) + P(B) A
• P(A) - P(B) B
• P(A) . P(B) C
• P(A) / P(B) D

If n is a positive integer then n! is

• (n - 1) (n - 2) .....3,.2.1 A
• n(n - 1) (n - 2) ...3.2.1 B
• n(n - 1 ) ( n -2) ... 3 C
• None of these D

• 
  A
• 
  B
• 
  C
• 
  D

Product of any n consecutive positive integers is divisible by

• n A
• √n B
• n! C
• None D

The probability that a person A will be alive 15 years hence is 5/7 and the probability that another person B will be alive 15 years hence is 7/9. Find the probability that both will be alive 15 years hence

• 4/63 A
• 5/9 B
• 45/49 C
• None of these D

• 
  A
• 
  B
• 
  C
• 
  D

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

• nPn A
• nPr B
• nCr C
• 2n D

There are 16 point in a plane, in which 6 are collinear. how many lines can be drawn by joining these points?

• 10 A
• 66 B
• 71 C
• 106 D

8 . 7 . 6. 5 in factorial form is

• 
  A
• 
  B
• 
  C
• 
  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 probability to get an odd number in a dice thrown once is

• 6 A
• 1 B
• 1/6 C
• 1/2 D

• 5 A
• 20 B
• 9 C
• 4 D

A die is thrown, the probability that the dots on the top are prime numbers or odd numbers is

• 1/2 A
• 2/3 B
• 1/3 C
• 2/5 D

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

• 950 A
• 760 B
• 1230 C
• 875 D

A box contains 10 red 30 white and 20 black marbles When a marble is drawn at random the probability that it is either red or white is

• 1/6 A
• 1/3 B
• 1/2 C
• 2/3 D