Business Mathematics

191. The equation 6x + y =7 will have a solution if
3x + y =4
-6x -2y = a

  1. a= -5
  2. a= -6
  3. a= -7
  4. a= -8
Correct answer: (D)
a= -8

192. If R is a relation from a finite set A having m elements to a finite set B having n elements, then the number of relations from A to B is

  1. 2mn
  2. 2mn -1
  3. 2mn
  4. Mn
Correct answer: (A)
2mn

193. Solve x +2y +3z = 85
3x +2y +2z = 105
2x +3y +2z = 110

  1. x =16, y=18, z=9
  2. x=15, y=20, z=10
  3. x=17, y=21, z=11
  4. x=12, y=22, z=12
Correct answer: (B)
x=15, y=20, z=10

194. Solve 2x –y -2z =0
x +2y -3z =9
3x –y -4z = 3

  1. x= -1, y=2, z =-2
  2. x=-2, y=1, z=-1
  3. x=2, y=-1, z=-2
  4. x=-1, y=3,z=-2
Correct answer: (A)
x= -1, y=2, z =-2

195. Solve x +2y –z =2 by finding inverse of the coefficient matrix
3x -4y +2z =1
-x +3y –z = 4

  1. x=2, y=3, z=4
  2. x=1, y=2, z=3
  3. x=2, y=-3, z=-4
  4. x=1, y=4, z=7
Correct answer: (D)
x=1, y=4, z=7

196. Are
1) 2x +4y -z = 5
2) y +z = 2
3) x + y +z = 7

  1. Equation 1 is dependent on 2 and 3
  2. Equation 2 is dependent on 1 and 3
  3. Equation 3 is dependent on 1 and 2
  4. Done of the above
Correct answer: (D)
Done of the above

197. If the set has p elements, b has q elements, the no of elements in A x B is

  1. p + q
  2. p + q + 1
  3. pq
  4. p2
Correct answer: (C)
pq

198. Let f(x) = x / x+ 3, then f (x + 1) =

  1. 3x + 2/ x+ 2
  2. x + 1 / x + 4
  3. (x + 1) / (x + 3)
  4. 2 x + 3 / (x + 3)
Correct answer: (B)
x + 1 / x + 4

199. If b = f(a) and f(a) = (a – 1) / (a + 1), which of the following is true?

  1. f(2a) = f(a) + 1
  2. f(1/a) = -f(a)
  3. a = f(b) + f(1/a)
  4. a = f(b)
Correct answer: (B)
f(1/a) = -f(a)

200. If A = {1, 2, 3}, B = {1,4,6, 9} and R is a relation from A to B defined by x is greater than y. The range of R is

  1. {1, 4, 6, 9}
  2. {4, 6, 9}
  3. {1}
  4. None of these
Correct answer: (C)
{1}
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