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- Question
- If one of the roots of the equation x 2 - bx + c = 0 is the square of the other, then which of the following option is correct?
Options- A. b3 = 3bc + c2 + c
- B. c3 = 3bc + b2 + b
- C. 3bc = c3 + b2 + b
- D. 3bc = c3 + b3 + b2
- Correct Answer
- b3 = 3bc + c2 + c
ExplanationGiven that, one root of the equation
x2 - bx + c = 0 is square of other root of this equation i.e., roots (?, ?2).
? Sum of roots = ? + ?2 = -(-b)/1
? ? (? + 1) = b .......(i)
and product of roots= ?. ?2 = c/1
? ?3 = c ? = c1/3 ....(ii)
From Eqs. (i) and (ii).
c1/3 (c1/3 + 1) = b ....(iii)
On cubing both sides, we get
c(c1/3 + 1)3 = b3
? c {c + 1 + 3c1/3 (c1/3 + 1)} = b3
? c {c + 1 = 3b} = b3 [from Eq. (iii)]
? b3 = 3bc + c2 + c - 1. A vessel, full of water, weighs 16.5 kg. When the vessel is (1/4)th full, it weight 5.25 kg. Then, weight of the empty vessel (in kg) is?
Options- A. 1.125
- B. 4.5
- C. 1.5
- D. 3 Discuss
- 2. A has twice as much money as B. They play together and at the end of the first game B wins one-third of A's money from A, what fraction of the sum that B now has, must A win black in the second game, so that they may have exactly equal money?
Options- A. 1/3
- B. 1/5
- C. 1/4
- D. 1/10 Discuss
- 3. Sum of three fractions is 2 11/ 24. If the greatest fraction is divided by the smallest fraction, the result is 7/6, which is greater than the middle fraction by 1/3. find all the three fractions?
Options- A. 3/5, 4/7, 2/3
- B. 7/8, 5/6, 3/4
- C. 7/9, 2/3, 3/5
- D. 7/8, 7/9, 7/10 Discuss
- 4. If the numerator of a fraction is increased by 200% and the denominator of the fraction is increased by 150%, the resultant fraction is 9/35. What is the original fraction?
Options- A. 3/10
- B. 2/15
- C. 3/16
- D. 2/7 Discuss
- 5. A, B, C and D purchase a gift worth ? 60. A pays 1/2 of what others are paying, B pays 1/3rd of what other are paying and C pays 1/4th of what others are paying. What is the amount paid by D?
Options- A. 14
- B. 15
- C. 16
- D. 13 Discuss
- 6. The degree f polynomial p(x) = x 3 + 1 + 2x = 6x + 1/x is?
Options- A. 2
- B. 4
- C. 3
- D. 5 Discuss
- 7. If x = 1 + ? 2, then what is the value of x 4 - 4x 3 + 4x 2?
Options- A. -1
- B. 0
- C. 1
- D. 2 Discuss
- 8. What is the solution of the equations x - y = 0.9 and 11(x + y) -1 = 2?
Options- A. x = 3.2, y = 2.3
- B. x = 1, y = 0.1
- C. x = 2, y = 1.1
- D. x = 1.2, y = 0.3 Discuss
- 9. The product of two alternate odd integers exceeds three times the smaller by 12. What is the larger integer?
Options- A. 9
- B. 7
- C. 3
- D. 5 Discuss
- 10. A sum of Rs. 13.50 is made by 38 coins which are either 50 paise or 25 paise. Find the number of 25 paise coins?
Options- A. 16
- B. 24
- C. 18
- D. 22 Discuss
More questions
Correct Answer: 1.5
Explanation:
Let the weight of vesel = x kg
Then, 1/4 of volume of water = (5.25 - x)kg
Full volume of water = (16.5 - x)
? 4(5.25 - x) = (16.5 - x)
? 21 - 4x = 16.5 - x
? 21 - 16.5 = 3x
? x = 4.5/3 = 1.5 kg
Correct Answer: 1/10
Explanation:
Let A has ? 200 at the starting of game, then B has ? 100 at the starting of game.
After the game, money left with A = 200 - 200/3 = ? 400/3
? Total money with B = 100 + 200/3 = ? 500/3
Let the fraction of money lost by B = N
Then, 500/3 - N x 500/3 = 400/3 + N x 500/3
? 500/3 - 400/3 = 500N/3 + 500N/3
? 100/3 = 1000N/3
? N = (100/3) x (3/1000) = 1/10
so, the fraction of money lost is 1/10.
Correct Answer: 7/8, 5/6, 3/4
Explanation:
Let the fraction be x, y and z respectively in decreasing order.
Then, according to the question,
x/z = 7/6
? x = 7z/6
And y = 7/6 - 1/3 = 7-2/6 = 5/6
Now, x + y + z = 211/24
? 7z/6 + 5/6 + z = 59/24
? (13z + 5)/ 6 = 59/24
? 13z = 59/4 - 5 =39/4
? z = 3/4
? x =7z/6 = 7/8
Hence, the fraction are 7/8, 5/6, 3/4.
Correct Answer:
Explanation:
Let the original fraction be p/q.
Numerator is increased by 200%.
? Numerator = p + 200% of p
= p + 200p/100
= p + 2p
= 3p
and denominator of the fraction is increased by 150%.
Denominator = q + 150q/100
= (100q + 150q)/100
= 250q/100
= 5q/2
Then, according to the question,
3p/5q/2 = 9/35
3p x 2/5q = 9/35
6p/5q = 9/35
? p/q = 9 x 5/35 x 6
p/q = 3/14
Correct Answer: 13
Explanation:
Let A, B, C and D pay ?x, ?y, ?z and ?a
According to the question,
x = 1/2(y + z + a)
2x = (y + z + a) ..........(i)
y = 1/3(x + z + a)
3y = (x + z + a) ...........(ii)
z = 1/4(x + y + a)
4z = (x + y + a) ..........(iii)
Also, x + y + z + a = 60 ...............(iv)
Now, put the value of x + y + a = 4z from (iii) in (iv)
Then, 4z + z = 60 ? 5z = 60
? z = 12
Similarly, on putting the value of x + z + a = 3y from (ii) in (iv), we get
3y + y = 60 = ? 4y = 60
? y = 15
Again, on putting the value of (y + z + a) = 2x from (i) in (iv), we get
2x + x = 60 ? 3x = 60
&ther4; x = 20
Now, x + y + z + a = 60
On putting the value of x, y and z, we get
12 + 15 + 20 + a = 60
? a = 60 - 47 = ? 13
Correct Answer: 4
Explanation:
x3 + 1 + 2x =6x + 1/x
x3 + 1 + 2x = (6x2 + 1)/x
(x3 + 1 + 2x)x = 6x2 + 1
x4 - 4x2 - 6x2 -1 =0
x4 - 4x2 + x - 1 =0
Degree of polynomial is highest exponent degree term i.e.,4.
Correct Answer: 1
Explanation:
x = 1 + ?2
? x4 - 4x3 + 4x2 = x2(x2 - 4x + 4)
= x2(x - 2)2
= (1 + ?2)2(1 + ?2 - 2)2
=(?2 + 1)2 (?2 - 1)2
=[(?2)2 - (1)2]2
=(2 - 1)2 =1
Correct Answer: x = 3.2, y = 2.3
Explanation:
x - y = 0.9 ...(i)
and 11(x + y)-1=2
? 11/ (x + y) = 2
? 2(x + y) =11
? x + y = 11/2 ...(ii)
On solving Eqs.(i) and (ii),we get
x = 3.2
and y = 2.3
Correct Answer: 7
Explanation:
Let two alternate odd integers odd integers be (2x+1) and (2x+5).
Then according to the question,
(2x + 1) (2x + 5) = 3(2x + 1) + 12
? (2x + 1) (2x + 5 - 3) = 12
? 2x2 + 3x - 5 = 0
On solving this quadratic equation,we get
x = 1 and x = -5/2
x = -5/2 is not a integer ? x = 1
Then, larger integer = 2x + 5 = 2 x 1 + 5 = 7
Correct Answer: 22
Explanation:
Let the number of 25 paise coins and 50 paise cons be x and y,respectively.
According to the question,
x + y = 38
Also, 25x + 50y = 1350
On multiplying Eq.(i) by 25 and substracting from Eq.(ii), we get y =16
On substituting the value of y in Eq.(i),we get y=22
So,the number of 25 paise coins in 22.
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