ECAT Pre Engineering Mathematic MCQ Test With Answer for Chapter 9 (Permutation, Combination and Probability)

Product of any n consecutive positive integers is divisible by

• n A
• √n B
• n! C
• None 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

The number of permutations of n objects of which there are n₁like of one kind, n₂like of the second kind and n₃like objects of third kind are

• 
  A
• 
  B
• 
  C
• 
  D

• 
  A
• 
  B
• 
  C
• 
  D

How many terms of the A.P 3,6,9,12,15...........must be taken to make the sum 108

• 8 A
• 6 B
• 7 C
• 36 D

Two coins are tossed twice each. The probability that the head appears on the first toss and the same forces appear in the two tosses is

• 1/4 A
• 1/2 B
• 1/3 C
• 1/7 D

A box containing 10 mangoes out of which 4 are rotter. Two mangoes are taken together from the box. If one of them is found to be good, the probability that the other is also good is

• 1 / 3 A
• 8 / 15 B
• 5 / 13 C
• 5 / 9 D

20. 19. 18. 17= _______

• 
  A
• 
  B
• 
  C
• 
  D

n different objects can be arranged taken all at a time in ______

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

6! = ______

• 360 A
• 720 B
• 6.5.4 C
• None of these D

Number of permutations of n distinct objects taken r(<n - 3) at a time which exclude 3(<n) particular objects is

• 3! P(n, r - 3) A
• P(n, 3) P(n, r - 3) B
• P(r, r)P(n, r - 3) C
• P(n - 3, r) D

Given two independent event A and B such that P(A) = 0.30 and P(B) = 0.60. Probability of getting neither A nor B is

• 0.28 A
• 0.13 B
• 0.12 C
• 0.42 D

Probability of an impossible event is

• 0 A
• -1 B
• 1 C
• ∞ D

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

• 
  A
• 
  B
• 
  C
• 
  D

The number of permutation that can be formed from the letters of the word OBJECT is

• 700 A
• 600 B
• 720 C
• 620 D

(n + 2) (n + 1) n= ______

• 
  A
• 
  B
• 
  C
• 
  D

• 
  A
• 
  B
• 
  C
• 
  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

5 unbiased coins coins are tossed simultaneously. The probability of getting at least one head is

• 1 / 32 A
• 31 / 32 B
• 1 / 16 C
• None of these D

How many different 5-digit even numbers are possible form digit 1,2,4,6,8

• 4 : 4! A
• 4! B
• 5! C
• 4!+4! D

• 
  A
• 
  B
• 
  C
• 
  D

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

• 
  A
• 
  B
• 
  C
• 
  D

For two events A and B if P(A) = P (A/B) = 1/4 and P(B/A) = 1/2, then

• A is sub-event of B A
• A and B are mutually exclusive B
• A and B are independent and P(A/B) = 3/4 C
• None of these D

• 1 / 2 A
• 1 / 3 B
• 1 / 4 C
• None of these D

The probability that a slip of numbers divisible by 4 is picked from the slips of number 1,2,3,4,......10 is

• 1/5 A
• 2/5 B
• 1/10 C
• 3/10 D

The value of n, when ⁿP₂= 20 is

• 3 A
• 4 B
• 6 C
• 5 D

The number of the diagonals of a 6 sided figure is

• 15 A
• 21 B
• 9 C
• 6 D

There are n seats round a table numbered 1, 2, 3 .... n. The number of ways in which m person can take seats is

• ⁿP_m A
• ⁿC_mx (m - 1) ! B
• ^n-1P_m C
• None of these D

In a school there are 150 students Out of these 80 students enrolled for mathematics class.50 enrolled for English class and 60 enrolled for Physics class The student enrolled for English cannot attend any other class but the students of mathematics and Physics can take two courses at a time find the number of students who have taken both physics and mathematics.

• 40 A
• 30 B
• 50 C
• 60 D

• 5 A
• 10 B
• 20 C
• 30 D