1 .A bag contains 5 white and 7 black balls and a man draws 4 balls at random. The odds against these being all black is :
Answer & Explanation
Answer : Option B |
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2 .The letters of the word SOCIETY are placed at random in a row. The probability that the three vowels come together is
A.$1\over6$ , B.$1\over7$ , C.$2\over7$, D.$5\over6$
Answer & Explanation
Answer : Option B |
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Explanation : |
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The word ‘SOCIETY’ contains seven distinct letters and they can be arranged at random in a row in $^7p_7$ ways, i.e. in 7! = 5040 ways
Let us now consider those arrangements in which all the three vowels come together. So in this case we have to arrange four letters. S,C,T,Y and a pack of three vowels in a row which can be done in $^5p_5$ i.e. 5! = 120 ways.
Also, the three vowels in their pack can be arranged in $^3p_3$ i.e. 3! = 6 ways.
Hence, the number of arrangements in which the three vowels come together is 120 × 6 = 720
∴ The probability that the vowels come together =
$720\over5040$=$1\over7$ |
3 .There are three events $E_1$,$E_2$,and $E_3$ One of which must, and only one can happen. The odds are 7 to 4 against $E_1$,5 to 3 against $E_2$ The odds against ,and $E_3$ is
Answer & Explanation
Answer : Option D |
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4 .
Answer & Explanation
Answer : Option D |
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5 .
Answer & Explanation
Answer : Option B |
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6 .A trader marked a watch 40% above the cost price and then gave a discount of 10%. He made a net profit of Rs.468 after paying a tax of 10% on the gross profit. What is the cost price of the watch?
Answer & Explanation
Answer : Option C |
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Explanation : |
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7 .By selling 8 dozen pencils, a shopkeeper gains the selling price of 1 dozen pencils. What is the gain?
A.12$^1\over2$ % , B.13$^1\over7$ % , C.14$^2\over4$ , D.87$^1\over2$ %
Answer & Explanation
Answer : Option C |
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Explanation : |
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8 .For what value of k, will the expression 3x 3 – kx 2 + 4x + 16 be divisible by $\left( x-\frac{ k}{2}\right)$ ?
Answer & Explanation
Answer : Option B |
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9 .
Answer & Explanation
Answer : Option A |
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10 .
Answer & Explanation
Answer : Option C |
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