Business Mathematics

171. The argument of (1 – i) / (1 + i) is

  1. – π / 2
  2. π / 2
  3. π 3 / 2
  4. 5 π / 2
Correct answer: (A)
– π / 2

172. How many terms of A.P. 21, 18, 15, 12, … must be taken to give the sum zero.

  1. 10
  2. 15
  3. 22
  4. 11
Correct answer: (B)
15

173. ( - 3 / 2) + (5 / 4) – (- 7 / 4)

  1. -2
  2. 2
  3. 7/4
  4. 3 / 2
Correct answer: (A)
-2

174. The two geometric means between the numbers 1 and 64 are

  1. 1 and 64
  2. 2 and 16
  3. 4 and 16
  4. 3 and 16
Correct answer: (C)
4 and 16

175. The union of infinite number of open sets is

  1. An open set
  2. A closed set
  3. Need not be an open set
  4. Not a set
Correct answer: (A)
An open set

176. The number of triangles that can be formed with 10 points as vertices, n of them being collinear, is 110. Then n is

  1. 3
  2. 4
  3. 5
  4. 6
Correct answer: (C)
5

177. In how many ways 4 men and 4 women can be seated in a row so that men and women are alternate?

  1. 28
  2. 36
  3. 4! 4!
  4. 2.4! 4!
Correct answer: (D)
2.4! 4!

178. The number of diagonals that can be drawn by joining the vertices of an octagon is

  1. 20
  2. 28
  3. 8
  4. 16
Correct answer: (A)
20

179. Find the 5th term in the expansion ( 1 -2x )-1

  1. 15x3
  2. 16x4
  3. 17x5
  4. 14x6
Correct answer: (B)

16x4

180. If in expansion of (1 +y)n the coefficient of the 5th, 6th and the 7th terms are in A.P the n is equal to

  1. 7, 11
  2. 7, 14
  3. 8, 16
  4. None of these
Correct answer: (B)
7, 14
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