Discussion
Home ‣ Aptitude ‣ Quadratic Equation See What Others Are Saying!
- Question
- In solving a problem, one student makes a mistake in the coefficient of the first degree term and obtain -9 and -1 for the roots. Another student makes a mistake in the constant term of the equation and obtains 8 and 2 for the roots. The correct equation was
Options- A. x2 + 10x + 9 = 0
- B. x2 - 10x + 16 = 0
- C. x2 - 10x + 9 = 0
- D. None of the above
- Correct Answer
- x2 - 10x + 9 = 0
ExplanationWhen mistake is done in first degree term, the roots of the equation are -9 and -1.
? Equation
(x+ 1) (x + 9) = x2 + 10x + 9 ...(i)
When mistake is done in constant term, the roots of equation are 8 and 2.
? Equation is
(x - 2) (x - 8) = x2 - 10x + 16 .....(ii)
? Required equation from Eqs. (i) and (ii) is
= x2 - 10x + 9
Also we see in both the cases 1st degree term is same with oposite sign i.e., in such questions we should take data from given conditions and find the correct equation. - 1. In a 200 m race, A can beat B by 50 m and B can beat C by 8 m. In the same race , A can beat C by what distance?
Options- A. 60 m
- B. 72 m
- C. 56 m
- D. 66 m Discuss
- 2. 26.823 x 27.923 x 4.5001 =?
Options- A. 3500
- B. 3450
- C. 3100
- D. 3400 Discuss
- 3. There are two inlets A and B connected to a tank. A and B can fill the tank in 16 h and 10 h, respectively. If both the pipes are opened alternately for 1 h, starting from A, then how much time will the tank take to filled?
Options- A. 131/4 h
- B. 116/8 h
- C. 122/5 h
- D. 121/4 h Discuss
- 4. If a + b + 1 = 0, then the value of (a 3 + b 3 + 1 ? 3ab) is
Options- A. 3
- B. 0
- C. ?1
- D. 1 Discuss
- 5. (2.247)3 + (1.730)3 + (1.023)3 - 3 x 2.247 x 1.730 x 1.023 / ( (2.247)2 + (1.730)2 + (1.023)2 - (2.247 x 1.730) - (1.730 x 1.023) - (2.247 x 1.023) )
Options- A. 1.730
- B. 4
- C. 5
- D. 5.247 Discuss
- 6. A cistern can be filled by two pipes in 30 and 40 minutes respectively. Both the pipes were opened at once, but after some time the first was shut up and the cistern was filled in 10 minutes more. How long after the pipes had opened was the first pipe shut up?
Options- A. 90/ 11 minutes
- B. 90/7 minutes
- C. 90/13 minutes
- D. 45/2 minute Discuss
- 7. In a camp, food was sufficient for 2000 people for 54 days. After 15 days, more people came and the food last only for 20 more days. How many people came?
Options- A. 1900
- B. 2400
- C. 1940
- D. 2220 Discuss
- 8. The area of the triangle formed by the lines 5x + 7y = 35, 4x + 3y = 12 and x-axis is
Options- A. 160 sq.unit 13
- B. 150 sq.unit 13
- C. 140 sq.unit 13
- D. 10 sq.unit Discuss
- 9. In a 20 m race, A runs at a speed of 2 m/s. If A gives B a start of 10 m and still beats him by 5 s, what will be the speed of B?
Options- A. 117/21 m/s
- B. 317/21 m/s
- C. 21 m/s
- D. 2 m/s Discuss
- 10. The length of a rectangular field is 100 m and its breadth is 40 m. What will be the area of the field?
Options- A. (4 x 102) sq m
- B. (4 x 10) sq m
- C. (4 x 104) sq m
- D. (4 x 103) sq m Discuss
More questions
Correct Answer: 56 m
Explanation:
According to the question, A : B = 200 : 150
and B : C = 200 : 192
? A : C = (A/B) x (B/C) = (200/150) x (200/192) = 200/144
So, A beats C by (200 - 177) = 56 m
Correct Answer: 3400
Explanation:
26.823 x 27.923 x 4.5001
? 27 x 28 x 4.5000 = 756 x 4.5000 = 3402 ? 3400
Correct Answer: 122/5 h
Explanation:
Part filled by A in 1 h = 1/16
Part fill by B in 1 h = 1/10
Part filled by ( A + B ) in 2 h = 1/16 + 1/10 = 13/80
? Part filled by ( A + B ) in 12 h = 6 x 13/80 = 78/80
? Remaining part = 1 - 78/80 = 2/80 = 1/40
Now, it is the turn of A
Time taken by A to fill 1/40 part of the tank = (1/40) x 16 = 2/5 h
? Total time taken ( 12 + 2/5) h = 122/5 h
Correct Answer: 0
Explanation:
As we know from the formula,
A3 + B3 + C3 = ( A + B + C) (A2 + B2 + C2 ? AB ? BC ? CA) + 3ABC
If A + B + C = 0 then,
A3 + B3 + C3 = 0 x (A2 + B2 + B2 ? AB ? BC ? CA) + 3ABC
A3 + B3 + C3 = 0 + 3ABC
A3 + B3 + C3 - 3ABC= 0
As we know that from given question,
A = a, B = b and C = 1, Put these value in above equation, we will get
a3 + b3 + 13 - 3 x a x b x 1 = 0
a3 + b3 + 1 - 3ab = 0
Correct Answer: 5
Explanation:
We know that, a3 + b3 + c3 - 3abc = (a + b + c ) ( a2 + b2 + c2 - ab - bc - ca )
? (a + b + c) = ( a3 + b3 + c3 - 3abc ) / ( a2 + b2 + c2 - ab - bc - ca ) .......................(i)
Given that in question,
(2.247)3 + (1.730)3 + (1.023)3 - 3 x 2.247 x 1.730 x 1.023 / (2.247)2 + (1.730)2 + (1.023)2 - (2.247 x 1.730) - (1.730 x 1.023) - (2.247 x 1.023)
Apply the formula given in Equation (i) and we will get,
= ( a + b + c )
= ( 2.247 + 1.730 + 1.023) [ from eq. (i) ]
= 5.000 = 5
Correct Answer: 90/7 minutes
Explanation:
Let the first pipe be shut up after x minutes
Now, applying the given rule, we have 30{1 - (x + 10)/40 } = x
[Here t = (x + 10) minutes]
or x = 90/7 minutes
Correct Answer: 1900
Explanation:
Correct Answer: 160 sq.unit 13
Explanation:
Correct Answer: 117/21 m/s
Explanation:
Time taken by A to cover 200 m = 200/2 = 100 s
? B covers (200 - 10) = 190 m in (100 + 5) = 105 s
? B' s speed = 190/105 = 38/21 = 117/21 m/s
Correct Answer: (4 x 103) sq m
Explanation:
Required area = Length x Breadth
= 100 x 40 = 4000 sq m
= 4 x 103 sq m
Comments
There are no comments.More in Aptitude:
Programming
Copyright ©CuriousTab. All rights reserved.