Recent questions tagged class11

The mean and standard deviation of 20 observations are found to be 10 and 2 respectively. On rechecking it was found that an observation 8 was incorrect. Calculate the correct mean and standard deviation If it is replaced by 12.

asked Jul 2, 2014 by meena.p

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A die has two faces each with number 1,three faces each with number 2 and one face with number 3.If die is rolled once,determine P(2)

asked Jul 2, 2014 by sreemathi.v

1 answer

4 cards are drawn from a well shuffled deck of 52 cards.What is the probability of obtaining 3 diamonds and one spade?

asked Jul 2, 2014 by sreemathi.v

1 answer

The mean and standard deviation of 20 observations are found to be 10 and 2 respectively. On rechecking it was found that an observation 8 was incorrect. Calculate the correct mean and standard deviation If wrong item is omitted.

asked Jul 2, 2014 by meena.p

1 answer

A box contain 10 red marbles,20 blue marbles and 30 green marbles.5 marbles are drawn from the box.What is the probability that atleast one will be green?

asked Jul 2, 2014 by sreemathi.v

1 answer

A box contain 10 red marbles,20 blue marbles and 30 green marbles.5 marbles are drawn from the box.What is the probability that all will be blue?

asked Jul 2, 2014 by sreemathi.v

1 answer

Given $\bar{x} $ is the mean and $\sigma^2$ is the variance of n observations $x_1,x_2,x_3......x_n$ prove that the mean and variance of the observations $ax_1,ax_2,ax_3.......ax_n$ are $a \bar{x}$ and $a^2\sigma^2$, respectively , $(a\neq 0)$

asked Jul 2, 2014 by meena.p

1 answer

In a class of 60 students,30 opted for NCC,32 opted for NSS and 24 opted for both NCC and NSS.If one of these student students is selected at random,find the probability that the student has opted NSS but not NCC

asked Jul 2, 2014 by sreemathi.v

1 answer

In a class of 60 students,30 opted for NCC,32 opted for NSS and 24 opted for both NCC and NSS.If one of these student students is selected at random,find the probability that the student has opted for neither NCC or NSS

asked Jul 2, 2014 by sreemathi.v

1 answer

In a class of 60 students,30 opted for NCC,32 opted for NSS and 24 opted for both NCC and NSS.If one of these student students is selected at random,find the probability that the student opted for NCC or NSS

asked Jul 2, 2014 by sreemathi.v

1 answer

The probability that a student will pass the final examination in both English and Hindi 0.5 and the probability of passing neither is 0.1.If the probability of passing the english examination is 0.75.What is the probability of passing the hindi examination?

asked Jul 2, 2014 by sreemathi.v

1 answer

In an entrance test that is graded on the basis of two examinations,the probability of a randomly chosen student passing the first examination is 0.8 and the probability of passing the second examination is 0.7.The probability of passing atleast one of them is 0.95.What is the probability of passing both?

asked Jul 2, 2014 by sreemathi.v

1 answer

In class XI of a school,40% of the students study mathematics and 30% study biology.10% of the class study both mathematics and biology.If a student is selected at random from the class.Find the probabilities that he will be studying mathematics or biology.

asked Jul 2, 2014 by sreemathi.v

1 answer

Find the equation of the line which passes through the point (– 4, 3) and the portion of the line intercepted between the axes is divided internally in the ratio 5 : 3 by this point

asked Jul 1, 2014 by thanvigandhi_1

1 answer

A straight line moves so that the sum of the reciprocals of its intercepts made on axes is constant. Show that the line passes through a fixed point. \[\] [ Hint : $\large\frac{x}{a}$$ + \large\frac{y}{b}$$=1$ where $ \large\frac{1}{a}$$+\large\frac{1}{b}$ = constant = $ \large\frac{1}{k}$ (say ). This implies that $ \large\frac{k}{a}$$+\large\frac{k}{b}$$=1 \Rightarrow $ line passes through the fixed point (k, k).]

asked Jul 1, 2014 by thanvigandhi_1

1 answer

In what direction should a line be drawn through the point (1, 2) so that its point of intersection with the line x + y = 4 is at a distance $ \large\frac{\sqrt 6}{3}$ from the given point

asked Jul 1, 2014 by thanvigandhi_1

1 answer

A variable line passes through a fixed point P. The algebraic sum of the perpendiculars drawn from the points (2, 0), (0, 2) and (1, 1) on the line is zero. Find the coordinates of the point P \[\] [Hint: Let the slope of the line be $m$. Then the equation of the line passing through the fixed point $P (x_1 , y_1 )$ is $y - y_1 = m (x - x_1 )$. Taking the algebraic sum of perpendicular distances equal to zero, we get $ y - 1 = m (x - 1). $ Thus $(x_1 , y_1 ) $ is $(1, 1)$.]

asked Jul 1, 2014 by thanvigandhi_1

1 answer

If the equation of the base of an equilateral triangle is x + y = 2 and the vertex is (2, – 1), then find the length of the side of the triangle \[\] [Hint: Find length of perpendicular (p) from (2, – 1) to the line and use $p = l \: \sin 60^{\circ}$, where $l$ is the length of side of the triangle]

asked Jul 1, 2014 by thanvigandhi_1

1 answer

Find the equation of one of the sides of an isosceles right angled triangle whose hypotenuse is given by 3x + 4y = 4 and the opposite vertex of the hypotenuse is (2, 2).

asked Jul 1, 2014 by thanvigandhi_1

1 answer

Find the equation of a straight line on which length of perpendicular from the origin is four units and the line makes an angle of $120^{\circ}$ with the positive direction of $x$ - axis.\[\] [Hint: Use normal form, here $ \omega =30^{\circ}$.]

asked Jul 1, 2014 by thanvigandhi_1

1 answer

The mean and standard deviation of six observations are $8$ and $4$ respectively. If each observation is multiplied by $3$, find the new mean and new standard deviation of the resulting observation.

asked Jul 1, 2014 by meena.p

1 answer

If the intercept of a line between the coordinate axes is divided by the point (–5 4) in the ratio 1 : 2, then find the equation of the line.

asked Jul 1, 2014 by thanvigandhi_1

1 answer

The mean and variance of $7$ observation are $8$ and $16$ respectively.If six of the observations are $2,4,10,12,14$. Find the remaining two observations.

asked Jul 1, 2014 by meena.p

1 answer

A and B are events such that $P(A)=0.42,P(B)=0.48,$P(A and B)=0.16.Determine P(A or B)

asked Jul 1, 2014 by sreemathi.v

1 answer

For what values of a and b the intercepts cut off on the coordinate axes by the line ax + by + 8 = 0 are equal in length but opposite in signs to those cut off by the line 2x – 3y + 6 = 0 on the axes.

asked Jul 1, 2014 by thanvigandhi_1

1 answer

A and B are events such that $P(A)=0.42,P(B)=0.48,$P(A and B)=0.16.Determine P(not B)

asked Jul 1, 2014 by sreemathi.v

1 answer

The mean and variance of eight observation are $9$ and $9.25$ respectively.If six of the observations are $6,7,10,12,12$ and $13$. Find the remaining two observations.

asked Jul 1, 2014 by meena.p

1 answer

A and B are events such that $P(A)=0.42,P(B)=0.48,$P(A and B)=0.16.Determine P(not A)

asked Jul 1, 2014 by sreemathi.v

1 answer

Events E and F are such that P(not E or not F)=0.25.state whether E and F are mutually exclusive.

asked Jul 1, 2014 by sreemathi.v

1 answer

If E and F are events .Such that $P(E)=\large\frac{1}{4}$$,P(F)=\large\frac{1}{2}$ and P(E and F)=$\large\frac{1}{8}$.Find P(not E and not F)

asked Jul 1, 2014 by sreemathi.v

1 answer

The sum and sum of squares corresponding to length x (in cm) and weight (y) in gm of 50 plant products are given below: $ \sum \limits _{i=1} ^{50} x_i=212, \qquad\sum \limits_{i=1}^{50}x_i^2 =902.8;\qquad \sum \limits _{i=1} ^{50} y_i=261, \qquad\sum \limits_{i=1}^{50}y_i^2 =1457.6$ Which is more varying , the length or weight?

asked Jul 1, 2014 by meena.p

1 answer

If E and F are events .Such that $P(E)=\large\frac{1}{4}$$,P(F)=\large\frac{1}{2}$ and P(E and F)=$\large\frac{1}{8}$.Find P( E or F)

asked Jul 1, 2014 by sreemathi.v

1 answer

Given $P(A)=\large\frac{3}{5}$ and $P(B)=\large\frac{1}{5}$.Find P(A or B),if $A$ and $B$ are mutually exclusive events .

asked Jul 1, 2014 by sreemathi.v

1 answer

Fill in the blanks : $P(A)=0.5,P(B)=0.35,P(A\cup B)=0.7,P(A\cap B)=$_________

asked Jul 1, 2014 by sreemathi.v

1 answer

Fill in the blanks : $P(A)=0.35,P(A\cap B)=0.25,P(A\cup B)=0.6,P(B)$=__________

asked Jul 1, 2014 by sreemathi.v

1 answer

Fill in the blanks :$P(A)=\large\frac{1}{3}$$,P(B)=\large\frac{1}{5}$$,P(A\cap B)=\large\frac{1}{15}$$,P(A\cup B)$=____________

asked Jul 1, 2014 by sreemathi.v

1 answer

Check whether the following probabilities P(A) and P(B) are consistently defined .$P(A)=0.5,P(B)=0.4,P(A \cup B)=0.8$

asked Jul 1, 2014 by sreemathi.v

1 answer

Check whether the following probabilities P(A) and P(B) are consistently defined .$P(A)=0.5,P(B)=0.7,P(A \cap B)=0.6$

asked Jul 1, 2014 by sreemathi.v

1 answer

In a lottery ,a person choose six,different natural numbers at random from 1 to 20 and if these six numbers match with the six numbers already fixed by lottery committee,he wins the prize.What is the probability of winning the prize in the game ?[Hint : Order of the numbers is not important]

asked Jul 1, 2014 by sreemathi.v

1 answer

Find the equation of the line passing through the point of intersection of 2x + y = 5 and x + 3y + 8 = 0 and parallel to the line 3x + 4y = 7.

asked Jul 1, 2014 by thanvigandhi_1

1 answer

The following is the record of goals scored by team A in a football session. For Team B , mean number of goals scored per match was 2 with a standard deviation 1.25 goals. Find which team may be considered more consistent ?

asked Jul 1, 2014 by meena.p

1 answer

A letter is selected at random from the word "ASSASSINATION".Find the probability that letter is a consonant

asked Jul 1, 2014 by sreemathi.v

1 answer

Find the equation of lines passing through (1, 2) and making angle $30^{\circ}$ with $y$ - axis.

asked Jul 1, 2014 by thanvigandhi_1

1 answer

A letter is selected at random from the word "ASSASSINATION".Find the probability that letter is a vowel

asked Jul 1, 2014 by sreemathi.v

1 answer

If $\large\frac{2}{11}$ is the probability of an event,what is the probability of the event 'not A'

asked Jul 1, 2014 by sreemathi.v

1 answer

An analysis of monthly wages paid to workers in two firms A and B , belonging to the same industry, gives the following results. (i) Which firm A and B pays larger amount as monthly wages. (ii) which firm A or B shows greater variability in individual wages?

asked Jul 1, 2014 by meena.p

1 answer

Three coins are tossed once.Find the probability of getting atmost 2 tails

asked Jul 1, 2014 by sreemathi.v

1 answer

Three coins are tossed once.Find the probability of getting no tail

asked Jul 1, 2014 by sreemathi.v

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Three coins are tossed once.Find the probability of getting exactly two tails

asked Jul 1, 2014 by sreemathi.v

1 answer

Three coins are tossed once.Find the probability of getting 3 tails

asked Jul 1, 2014 by sreemathi.v

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