# Aptitude Questions: Quadratic Equations Set 21

Hello Aspirants. Welcome to Online Quantitative Aptitude Section in AffairsCloud.com. Here we are creating sample questions in Quadratic Equations which is common for all the competitive exams. We have included Some questions that are repeatedly asked in bank exams !!!

1. 5x + 2y = 31
3x + 7y = 36
A. X > Y
B. X < Y
C. X ≥ Y
D. X ≤ Y
E. X = Y or relation cannot be established
A. X > Y
Explanation:

5x + 2y = 31 —-(1)
3x + 7y = 36 —-(2)
By solving eqn(1) and (2)
x = 5 ; y = 3

2. x2 – x – √3x + √3= 0
y2 – 3y + 2 = 0
A. X > Y
B. X < Y
C. X ≥ Y
D. X ≤ Y
E. X = Y or relation cannot be established
E. X = Y or relation cannot be established
Explanation:

x2 – x – √3x + √3= 0
x (x-1) – √3(x -1) = 0
(x-1) (x-√3) = 0
x = 1, 1.732
y2 – 3y + 2 = 0
y2 – y – 2y + 2 = 0
y = 1, 2
Put on number line
1, 1, 1.732, 2

3. [48 / x4/7] – [12 / x4/7] = x10/7
y³ + 783 = 999
A. X > Y
B. X < Y
C. X ≥ Y
D. X ≤ Y
E. X = Y or relation cannot be established
D. X ≤ Y
Explanation:

(48 – 12) / x4/7 = x10/7
36 = x(10/7 + 4/7)
36 = x2
x =  ± 6
y3 + 783 = 999
y3 = 999 – 783
y3 = 216
y = 6
Put on number line
-6, 6, 6

4. 172 + 144 ÷ 18 = x
262 – 18 * 21 = y
A. X > Y
B. X < Y
C. X ≥ Y
D. X ≤ Y
E. X = Y or relation cannot be established
B. X < Y
Explanation:

172 + 144 ÷ 18 = x
x = 297
262 – 18 * 21 = y
y = 676 – 378 = 29

5. 5/7 – 5/21 = √x/42
√y/4 + √y/16 = 250/√y
A. X > Y
B. X < Y
C. X ≥ Y
D. X ≤ Y
E. X = Y or relation cannot be established
B. X < Y
Explanation:

5/7 – 5/21 = √x/42
10/21 = √x/42
√x = 20
x = 400
√y/4 + √y/16 = 250/√y
5√y/16 = 250/√y
y = 800

6. 9/√x + 19/√x = √x
y5 – [(28)11/2 /√y] = 0
A. X > Y
B. X < Y
C. X ≥ Y
D. X ≤ Y
E. X = Y or relation cannot be established
E. X = Y or relation cannot be established
Explanation:

9/√x + 19/√x = √x
x = 28
y5 – [(28)11/2 /√y] = 0
y11/2 = (28)11/2
y = 28

7. 12/√x – 23/√x = 5√x
√y/12 – 5√y/12 = 1/√y
A. X > Y
B. X < Y
C. X ≥ Y
D. X ≤ Y
E. X = Y or relation cannot be established
A. X > Y
Explanation:

12/√x – 23/√x = 5√x
-11 = 5x
x = -2.2
√y/12 – 5√y/12 = 1/√y
√y[1/12 – 5/12]= 1/√y
y = -3

8. 7x + 6y + 4z = 122
4x + 5y + 3z = 88
9x + 2y + z = 78
A. X < Y = Z
B. X ≤ Y < Z
C. X < Y > Z
D. X = Y > Z
E. X = Y = Z or relation cannot be established
A. X < Y = Z
Explanation:

7x + 6y + 4z = 122 —(1)
4x + 5y + 3z = 88 —(2)
9x + 2y + z = 78 —(3)
From (1) and (2) => 5x – 2y =4 —(a)
From (2) and (3) => 23x + y = 146 —(b)
From (a) and (b) => x = 6, y = 8. Put values in eqn (3) => z = 8

9. (x+y)³ = 1331
x – y + z = 0
xy = 28
A. X < Y = Z
B. X ≤ Y < Z
C. X < Y > Z
D. X = Y > Z
E. X = Y = Z or relation cannot be established
E. X = Y or relation cannot be established
Explanation:

(x + y)³ = 1331
x + y = 11 —(a)
(x + y)2 = 121
(a + b)2 – (a – b)2 = 4ab
(x – y)2 + 4xy = 121
x – y = 3 —(b)
From eqn (a) and (b)
x = 7; y = 4 Put values in eqn (2) => z = -3

10. 7x + 6y = 110
4x + 3y = 59
x + z = 15
A. X < Y = Z
B. X ≤ Y < Z
C. X < Y > Z
D. X = Y > Z
E. X = Y = Z or relation cannot be established
C. X < Y > Z
Explanation:

7x + 6y = 110 —(1)
4x + 3y = 59 —(2)
x + z = 15 —(3)
From eqn(1) and (2)
x = 8; y = 9 Put values in eqn (3) => z = 7

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