In a box, there are 20 marbles. Each marble is marked with a distinct number from 1 to 20. Find the probability of drawing a marble from the box which is marked with a number that is a perfect square.
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A man takes a step forward with probability 0.4 and backward with probability 0.6. Find the probability that at the end of 5 steps, he is one step awa
The man can be one stap away from the statting point if (i) either he is one stgep aheld or (ii) one step behind the starting point. Now if at...
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A die is thrown a fixed number of times. If probability of getting even number 3 times is same as the probability of getting even number 4 times, then
Correct Answer - D According to the givn condition, `""^(n)C_(3)((1)/(2))^(n)=""^(n)C_(4)((1)/(2))^(n),` where n is the number of times die is thrown. `therefore""^(n)C_(3)=""^(n)C_(4)impliesn=7` Thus, the required probability is `=""^(7)C_(1)((1)/(2))^(7)=(7)/(2^(7))=(7)/(128)`
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The box contains tickets numbered from 1 to 20. Three tickets are drawn from the box with replacement. The probability that the largest number on the
Correct Answer - D Let X denote the largest number on the 3 sticks drawn. Then, `P(Xle7)=(7//20)^(3)and P(Xle6)=(6//20)^(3).` Then, the required probability is `P(X=7)=((7)/(20))^(3)-((6)/(20))^(3)`
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A boy has a collection of blue and green marbles. The number of blue marbles belong to the set `{2,3,4,…..,13}`. If two marbles are chosen simultaneou
Correct Answer - A::B::C `(a,b,c)` Let the no. of blue marbles is `a` and no. of green marbles is `b` . `:.(ab)/("^(a+b)C_(2))=(1)/(2)` `implies(a+b)(a+b-1)=4ab` `impliesb^(2)-(2a+1)b+a^(2)-a=0` but `b in R implies D=(2a+1)^(2)-4(a^(2)-a)=8a+1` `:....
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A box contains 50 tickets. Each ticket is numbered from 1 to 50. One ticket is selected at random, find the probability that the number on the ticket
Correct Answer - `(43)/(50)`
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There are two boxes, red and white in colour. The ratio of the number of chocolates in the white box to the number of biscuits in the red box is ` 3 :
Correct Answer - ` 18 : 13`
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There is certain number of rows of chairs in a room .The number of chairs in each row is thrice the total number of rows. Find the number of charis in
Correct Answer - 81,27
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the selling price and the marked price of an article are Rs 132 x and Rs 165x respectively . If the article is marked 65% above the cost price and a d
Correct Answer - `192`
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Amar ,Bhuvan and Chetan have some marble with them. Bhuvan has 20% more marbles than Amar and Chetan has 10% less marbles than Bhuvan . If the total n
Correct Answer - `120`
2 Answers 1 views
(i) A box contins 80 discs, which are numbered from 1 to 80. If one disc is drawn at random from the box, find the probability that it bears a perfect
Correct Answer - ` (i) 1/10 (ii) (a) 9/10 (b) 1/5`
2 Answers 1 views