Subject

Mathematics

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

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 Multiple Choice QuestionsLong Answer Type

31.

Using integration, find the area of the region bounded by the triangle whose vertices are (-1, 2), (1, 5) and (3, 4).

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32.

A manufacturing company makes two types of teaching aids A and B of Mathematics for class XII. Each type of A requires 9 labour hours of fabricating and 1 labour hour for finishing. Each type of B requires 12 labour hours for fabricating and 3 labour hours for finishing. For fabricating and finishing, the maximum labour hours available per week are 180 and 30 respectively. The company makes a profit of 80 on each piece of type A and 120 on each piece of type B. How many pieces of type A and type B should be manufactured per week to get a maximum profit? Make it as an LPP and solve graphically. What is the maximum profit per week?

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33.

There are three coins. One is a two-headed coin (having head on both faces), another is a biased coin that comes up heads 75% of the times and third is also a biased coin that comes up tails 40% of the times. One of The three coins is chosen at random and tossed, and it shows heads. What is the probability that it was the two-headed coin?

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34.

Two numbers are selected at random (without replacement) from the first six positive integers. Let X denote the larger of the two numbers obtained. Find the probability distribution of the random variable X, and hence find the mean of the distribution.


If 1 is the smallest number,
the other numbers are:2,3,4,5,6
If 2 is the smallest number, the other numbers are:3,4,5,6
If 3 is the smallest number, the other numbers are:4,5,6
If 4 is the smallest number, the other numbers are: 5, 6
If 5 is the smallest number, the other number is:6
Thus comma space the space sample space space space is space straight S space equals space open curly brackets table row cell 12 comma space 13 comma space 14 comma space 15 comma space 16 end cell row cell 23 comma space 24 comma space 25 comma space 26 end cell row cell 34 comma space 35 comma space 36 end cell row cell 45 comma space 46 end cell row 56 end table close curly brackets
Thus, there are 15 set of numbers in the sample space. 
Let X be
X:           2             3                  4                 5                   6
straight P left parenthesis straight X right parenthesis colon      1/15        2/15             3/15            4/15               5/15
We know that,
straight E left parenthesis straight X right parenthesis space equals space straight X subscript straight i straight P left parenthesis straight X subscript straight i right parenthesis
equals space 2 cross times 1 over 15 plus 3 cross times 2 over 15 plus 4 cross times 3 over 15 plus 5 cross times 4 over 15 plus 6 cross times 5 over 15
equals fraction numerator 2 plus 6 plus 12 plus 20 plus 30 over denominator 15 end fraction
equals 70 over 15
almost equal to space 4.66



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35.

Evaluate:
integral fraction numerator 1 over denominator sin to the power of 4 straight x plus sin squared xcos squared straight x plus cos to the power of 4 straight x end fraction dx

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