Mathematics - Online Test

Q1. A manufacturer produces nuts and bolts. It takes 1 hour of work on machine A and 3 hours on machine B to produce a package of nuts. It takes 3 hours on machine A and 1 hour on machine B to produce a package of bolts. He earns a profit of Rs17.50 per package on nuts and Rs 7.00 per package on bolts. How many packages of each should be produced each day so as to maximise his profit, if he operates his machines for at the most 12 hours a day?
Answer : Option B
Explaination / Solution:

Let number of packages of nuts produced = x
And number of packages of bolts produced = y
Therefore , the above L.P.P. is given as :
Maximise , Z = 17.50x +7y , subject to the constraints : x +3y ≤ 12 and. 3x +y ≤ 12, x, y ≥ 0.

Corner points

Z =17.50 x +7 y

O( 0 , 0 )

0

D(4,0 )      

70

A(0,4)

28

B(3,3)

73.50…………………(Max.)

Here Z = 73.50 is maximum.
i.e 3 packages of nuts and 3 packages of bolts;
Maximum profit = Rs 73.50.


Q2. Solve the system of inequalities − 2 < 1 − 3x < 7
Answer : Option B
Explaination / Solution:



Q3.

Tangents to the curve  at the points (1, 1) and ( – 1, 1)


Answer : Option D
Explaination / Solution:

 therefore , slope of tangent at (1,1) = - 1 and the slope of tangent at ( - 1 ,1 )= 1 .

Now product of the slopes=1.-1= -1

Hence , the two tangents  are at right angles.


Q4. The number of numbers between 105 and 1000 which are divisible by 7 is
Answer : Option B
Explaination / Solution:



Q5. If the median = (mode + 2 mean) μ, then μ is equal to
Answer : Option C
Explaination / Solution:



Q6. The area bounded by the parabola  and the line x + y = 3 is
Answer : Option B
Explaination / Solution:



Q7. Let L be the set of all lines in a plane and R be the relation on L defined as R = {(L1, L2): L1 is perpendicular to L2}. Then R is
Answer : Option B
Explaination / Solution:

The relation R is symmetric only , because if L1 is perpendicular to L2 ,then L2 is also perpendicular to L1,but no other cases that is reflexive and transitive is not possible.

Q8.
Answer : Option D
Explaination / Solution:



Q9. The equations of the lines through ( - 1 , - 1 ) and making angles of  with the line x + y = 0 are
Answer : Option D
Explaination / Solution:

The lines x+1=0 and y+1=0 are perpendicular to each other.

The slope of the line x+y =0 is -1

Hence the angle made by this line with respect to X axis is 450

In other words the angle made by this line with x+1=0 is 450

Clearly the other line with which it can make 450 is y+1=0

 


Q10. If x = 5 and y = - 2 , then x – 2y = 9 . The contrapositive of this proposition is
Answer : Option D
Explaination / Solution:

p: x = 5 and y = - 2 , q : x – 2y = 9

The contrapositive of 

Hence If x – 2y  9 , then x  5 or y  - 2