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- 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. x% of y is y% of?
Options- A. x
- B. 100x
- C. x/100
- D. y/100 Discuss
- 2. If 37 1/ 2% of a number is 900,then 62 1/ 2% of the number is?
Options- A. 1200
- B. 1350
- C. 1500
- D. 540 Discuss
- 3. Subtracting 6% of A from A is equivalent to multiplying A by how much?
Options- A. 0.94
- B. 9.4
- C. 0.094
- D. 94 Discuss
- 4. The price of rice has increased by 60%. In order to restore to the original price, the new price must be reduced by?
Options- A. 331/3%
- B. 371/2%
- C. 40%
- D. 45% Discuss
- 5. ? (3.6% of 40) is equal to?
Options- A. 2.8
- B. 1.8
- C. 1.2
- D. None of these Discuss
- 6. A student is required to secure at least 50% marks in order to pass an examination. He secured 50 marks which were less than the minimum passing marks by 50. The maximum marks of the paper are?
Options- A. 200
- B. 250
- C. 275
- D. 300 Discuss
- 7. A furniture seller sells two tables at ? 1500 each. He earned a profit of 20% on one table and suffered a loss of 20% on the another table. Net profit or loss in this deal is?
Options- A. 4% loss
- B. 4% profit
- C. 10% loss
- D. 10% profit Discuss
- 8. What is 5% of 50% of 500?
Options- A. 12.5
- B. 25
- C. 1.25
- D. 6.25 Discuss
- 9. 25% of what amount of money is equal to 12 1/ 2 of ? 180?
Options- A. ? 120
- B. ? 75
- C. ? 80
- D. ? 90 Discuss
- 10. The monthly income of a person is ? 5000. If his income is increased by 30% then what is his monthly income now?
Options- A. ? 7000
- B. ? 5500
- C. ? 4500
- D. ? 6500 Discuss
More questions
Correct Answer: x
Explanation:
Let x% of y = y% of A, then
? xy / 100 = yA/100
? A = (xy/100) x (100/y) = x
Correct Answer: 1500
Explanation:
Let 371/2% of A = 900
? {(75/2) x A} x 100 = 900
? A = (900 x 2 x 100) / 75 = 2400
So, 621/2% of A = (125/2) x (1/100) x 2400 =1500
Correct Answer: 0.94
Explanation:
Let A - 6% of A = AB.
? (94 x A) / 100 = AB
? B = 0.94
Correct Answer: 371/2%
Explanation:
Let original price = Rs. 100
? Increase price = Rs. 160
? Decrease on Rs. 160 = Rs. 60
? Decrease on Rs. 100 = (60/160) x 100 % = 371/2%
Correct Answer: 1.2
Explanation:
?(3.6/100) x 40
= ?1.44 = 1.2
Correct Answer: 200
Explanation:
Minimum passing marks = 50 + 50 = 100
Let the total marks = x
Then, 50% of x = 100
? x = (100/50) x 100 = 200
Correct Answer: 4% loss
Explanation:
Profit or loss percent = ab/100 %
= (20 x 20)/100 %
= -4%
Correct Answer: 12.5
Explanation:
5% of 50% of 500
= (5/100) x (50/100) x 500
= 12.5
Correct Answer: ? 90
Explanation:
Let the required amount of money be N.
Then, N x 25% = 180 x 121/2%
? N = (180 x 12.5)/25
= ? 90
Correct Answer: ? 6500
Explanation:
Monthly income of a person = ? 5000
Increment in income = (30/100) x 5000 = 1500
New income = 5000 + 15000 = ? 6500
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