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- Question
- In a two-digit number, the digit at the unit's place is 1 less than twice the digit at the ten's place. If the digits at unit's and ten's place are interchanged, the difference between the new and the original number is less than the original number by 20. The original number is
Options- A. 47
- B. 59
- C. 23
- D. 35
- Correct Answer
- 47
ExplanationSince two digit number = 10p + q
According to question , ? q = 2p ? 1.. (i)
When digits are interchanged then new number = 10q + p
then original number ? [new number ? original number] = 20
? 10p + q ? [10q + p ? (10p + q)] = 20
? 10p + q ? 10q ? p + 10p + q = 20
19p ? 8q = 20
19p ? 8 (2p ? 1) = 20 (Using eq. (i))
19p ? 16p + 8 = 20
3p = 12 ? p = 4
From (i) q = 2 × 4 ? 1 ? q = 7
? original number = 10p + q = 10 × 4 + 7 = 47 - 1. A man buys 3 cows and 18 goats in ? 47,200. Instead if he would have bought 8 cows and 3 goats, he had to pay ? 53,000 more. Cost of one cow is:
Options- A. ? 10,000
- B. ? 11,000
- C. ? 12,000
- D. ? 13,000 Discuss
- 2. If the square of the sum of two numbers is equal to 4 times of their product. then the ratio of these numbers is:
Options- A. 2 : 1
- B. 1 : 3
- C. 1 : 1
- D. 1 : 2 Discuss
- 3. If a2 + b2 + c2 = 2 (a ? b ? c) ? 3, then the value of 2a ? 3b + 4c is
Options- A. 1
- B. 7
- C. 2
- D. 3 Discuss
- 4. Let a = ?6 - ?5, b = ?5 - 2, c = 2 - ?3 Then point out the correct alternative among the four alternatives given below.
Options- A. a < b < c
- B. b < a < c
- C. a < c < b
- D. b < c < a; Discuss
- 5. If the difference of two numbers is 3 and the difference of their squares is 39; then the larger number is:
Options- A. 9
- B. 12
- C. 13
- D. 8 Discuss
- 6. The linear equation such that each point on its graph has an ordinate four times its abscissa is:
Options- A. y + 4x = 0
- B. y = 4x
- C. x = 4y
- D. x + 4y = 0 Discuss
- 7. 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
- 8. Find the remainder when f(x) = x 4 - 6x 3 + 2x 2 + 3x + 1 is divided by (x - 2)?
Options- A. -12
- B. 12
- C. 17
- D. -17 Discuss
- 9. If the polynomials ax 3 + 4x 2 -3x - 4 and x 3 - 4x + a leave the same remainder when divided by (x - 3). Then, what is the value of a?
Options- A. 2
- B. -1
- C. 3
- D. 4 Discuss
- 10. A student was asked to find 2/5th of a number and he instead multiplied it by 5/2. As a result he got an answer which was more than the correct answer by 5208. What was the number?
Options- A. 2485
- B. 2456
- C. 2480
- D. 2455 Discuss
Elementary Algebra problems
Search Results
Correct Answer: ? 12,000
Explanation:
Correct Answer: 1 : 1
Explanation:
Let the number be p and q.
According to question,
(p + q)2 = 4pq
? p2 + q2 + 2pq ? 4pq = 0
? (p ? q)2 = 0
? p = q
Hence , required ratio is 1 : 1 .
Correct Answer: 1
Explanation:
Given that :- a2 + b2 + c2 = 2 (a ? b ? c) ? 3
? a2 + b2 + c2 - 2 (a ? b ? c) + 3 = 0
? a2 + b2 + c2 - 2a + 2b + 2c + 3 = 0
? ( a2 + 1 - 2a ) + ( b2 + 1 + 2b ) + ( c2 + 1 + 2c ) = 0
? ( a - 1 )2 + ( b + 1 )2 + ( c + 1 )2 = 0
This is possible when ( a - 1 )2 = 0, ( b + 1 )2 = 0, and ( c + 1 )2 = 0
? a = 1, b = ?1, c = ?1
Thus, 2a ? 3b + 4c = 2 (1) ? 3 (?1) + 4 (?1)
2a ? 3b + 4c = 2 + 3 ? 4 = 1.
Correct Answer: a < b < c
Explanation:
We know that , ?6 = 2.44, ?5 = 2.23, ?3 = 1.73
a = ?6 - ?5 = 2.44 - 2.23 = 0.21
b = ?5 - 2 = 2.23 - 2 = 0.23
c = 2 - ?3 = 2 - 1.73 = 0.27
Correct Answer: 8
Explanation:
Let the numbers are p and q.
p ? q = 3 ? (1)
p2 ? q2 = 39
(p ? q) (p + q) = 39 ? x + y = 13 ? (2)
Adding eqn (1) and (2)
p + q + p ? q = 16 ? p = 8
? q = 3
Hence, 8 is the larger number.
Correct Answer: y = 4x
Explanation:
The linear equation is y = 4x,
When, x = 1, y = 4
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.
Correct Answer: -17
Explanation:
When f(x) = x4 - 6x3 + 2x2 + 3x + 1 is divided by (x - 2), then remainder can be calculated by putting x - 2 = 0
i.e. x = 2
Now, put x = 2 in f(x)
f(2) = (2)4 - 6(2)3 + 2(2)2 + 3 x 2 + 1
= 16 - 48 + 8 + 6 + 1 = -17
? The remainder will be - 17.
Correct Answer: -1
Explanation:
Since, p(x) = ax3 + 4x2 + 3x - 4 and q(x) = x3 -4x + a divided by x - 3, hence p(3) = q(3)
? a x 33 + 4 x 32 + 3 x 3 - 4 = 33 - 4 x 3 + a
? a = -1
Correct Answer: 2480
Explanation:
Let the number be x. Then,
5x/2 - 2x/5 = 5208
? (25x - 4x)/10 = 5208
? 21x/10 = 5208
? 21x = 5208 x 10
? x = (5208 x 10)/21
? x = 2480
So, the original numbers was 2480.
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