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- Question
(3x + 2) (2x - 5) = ax˛ + kx + n . What is the value of a - n + k ?
Options- A. 5
- B. 8
- C. 9
- D. 10
- Correct Answer
- 5
ExplanationThis is a quadratic equation. To find n we multiply the last terms in each bracket together (2 times -5) = -10
To find ?a? we multiply the first terms in each bracket together (3x times 2x) = 6x2, So a = 6.
Thus a - n = 16
To find k we multiply the first term in the first bracket by the second term in the second bracket and add the result to the product of the second term in the first bracket and the first term in the second. (-15x + 4x) = -11x. So k = -11
16 - 11 = 5
- 1. The sum of the digits of a two-digit number is 9 less than the number. Which of the following digits is at unit's place of the number ?
Options- A. 1
- B. 2
- C. 3
- D. data inadequate Discuss
- 2. If 1 is added to the denominator of a traction, the fraction becomes 1/2. If 1 is added to the numerator of the fraction, the fraction becomes 1. The fraction is :
Options- A. 1/3
- B. 2/3
- C. 4/3
- D. 5/3 Discuss
- 3. A number is doubled and 9 is added. If the resultant is trebled, it becomes 75. What is that number ?
Options- A. 2
- B. 4
- C. 6
- D. 8 Discuss
- 4. What is the common ratio of the following geometric sequence? 4, 2, 1, 0.5, 0.25, 0.125,...
Options- A. 0.5
- B. -1
- C. 1.5
- D. -0.5 Discuss
- 5. Find the number which multiplied by 15 is increased by 56 ?
Options- A. 6
- B. 4
- C. 3
- D. 12 Discuss
- 6. A person in a bet 40 shots taken. 50p for a hit, 10p for a miss.(he have to give). Finally he has Rs.5. How many hits he have ?
Options- A. 15
- B. 20
- C. 25
- D. 30 Discuss
- 7. The sum of the two digits of a number is 8. If the number is subtracted from the number obtained by reversing its digits, the result is 54. Find the number ?
Options- A. 28
- B. 19
- C. 37
- D. 17 Discuss
- 8. One number is 25% of another number. The larger number is 12 more than the smaller. The large number is
Options- A. 48
- B. 16
- C. 4
- D. 12 Discuss
- 9. How many numbers are there from 2000 to 7000 which are both perfect squares and perfect cubes?
Options- A. 0
- B. 1
- C. 2
- D. 3 Discuss
- 10. If in a two digit number, the digit at unit place is z and the digit at tens place is 8, then the number is
Options- A. 80z + z
- B. 80 + z
- C. 8z + 8
- D. 80z + 8 Discuss
Problems on Numbers
Search Results
Correct Answer: data inadequate
Explanation:
Let the ten's digit be x and unit's digit be y. Then, (10x + y) - (x + y) = 9 or x = 1.
From this data we cannot find y, the unit's digit. So the data is inadequate..
Correct Answer: 2/3
Explanation:
Let the fraction be x/y. Then, x /(y+1) = 1/2
=> 2x - y = 1 ..........(i)and
(x + 1) / y = 1 => x - y = 1 .......(ii)
Solving (i) and (ii), we get : x = 2, y = 3. Hence, the required fraction is 2/3..
Correct Answer: 8
Explanation:
Let the number be v. Then, 3 (2x + 9) = 75.
2x + 9 = 25
=> 2x = 16
=> x = 8
Correct Answer: 0.5
Explanation:
In mathematics, a geometric progression, also known as a geometric sequence, is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio.
Herein the given sequence, 4, 2, 1, 0.5, 0.25, 0.125,...
Common Ratio r = 2/4 = 1/2 = 0.5/1 = 0.25/0.5 = 0.125/0.25 == 0.5.
Correct Answer: 4
Explanation:
Let the number be x. Then,
15x - x = 56
x = 4
Correct Answer: 15
Explanation:
Let number of hit shots be 'X'
Let number of miss shots be 'Y'
Given X + Y = 40....(1)
50X - 10Y = 500.....(2)
Solving 1 and 2, we get
X = 15 and Y = 25
Therefore, number of hits = 15
Correct Answer: 17
Explanation:
Any two digit number can be written as (10P + Q), where P is the digit in the tens place and Q is the digit in the units place.
P + Q = 8 ----- (1)
(10Q + P) - (10P + Q) = 54
9(Q - P) = 54
(Q - P) = 6 ----- (2)
Solve (1) and (2) P = 1 and Q = 7
The required number is = 17
Correct Answer: 16
Correct Answer: 1
Correct Answer: 80 + z
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