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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
Explanationlet us assume the ten's digit number be x and unit's place digit be y.
Then two digit Original Number = 10x + y
According to question ? y = 2x - 1 ................(1)
When digits are interchanged then new number = 10y + x
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,
New Number - Original Number = Original number - 20
? 10y + x - (10x + y) = 10x + y - 20
? 10y + x - 10x - y - 10x - y = - 20
? 8y - 19x = - 20
? 19x - 8y = 20 ...................(2)
Put the value of y from equation (1) in above equation (2).
? 19x - 8(2x - 1) = 20
? 19x - 16x - 8 = 20
? 7x = 20 + 8
? 7x = 28
? x = 28/7
? x = 4
Put the value of y in equation (1)
From (i) y = 2 x 4 -1 = y = 7
? original number = 10x + y =10 x 4 + 7 = 47. - 1. Five coins are tossed at a time. Then, the probability of obtaining at least one tail is
Options- A. 31/32
- B. 1/32
- C. 1/5
- D. 5/32 Discuss
- 2. Find the maximum number of tree which can plant 20 m apart on the two side of straight road 1760 m long
Options- A. 174
- B. 176
- C. 180
- D. 178 Discuss
- 3. 1307 x 1307 =?
Options- A. 1601249
- B. 1607249
- C. 1701249
- D. 1708249 Discuss
- 4. The circumferences of two concentric are 176 m and 132 m respectively. what is the difference between their radii?
Options- A. 5 meter
- B. 7 meter
- C. 8 meter
- D. 44 meter Discuss
- 5. (1/2 ÷ 4 + 20) / (1/2 x 4 + 20) =?
Options- A. 81 / 88
- B. 23/11
- C. 161 / 176
- D. 1 Discuss
- 6. Find the cardinal number of the following set {x: x = 2n, n ? N, 4 ? x ? 11}
Options- A. 8
- B. 6
- C. 12
- D. 4 Discuss
- 7. If a fraction is multiplied by itself and then divided by the reciprocal of the same fraction, the result is 18 26/ 27. Find the fraction.
Options- A. 8/27
- B. 11/3
- C. 22/3
- D. 32/3 Discuss
- 8. (0.04) 3 =?
Options- A. 0.064
- B. 0.0064
- C. 0.00064
- D. 0.000064 Discuss
- 9. If a + b + c = 8, then the value of (a ? 4)3 + (b ? 3)3 + (c ? 1)3 ? 3 (a ? 4) (b ? 3) (c ? 1) is
Options- A. 2
- B. 4
- C. 1
- D. 0 Discuss
- 10. 3571 +? - 6086 = 155
Options- A. 2400
- B. 2630
- C. 2515
- D. None of these Discuss
More questions
Correct Answer: 31/32
Explanation:
Total events = n (s) = 25 = 32
n(E) of getting heads = 1
p(E) = 1/32
? n(E) = 1 - p(E) = 1 - 1/32 = 31/32
Correct Answer: 178
Explanation:
Number of trees that can be planted on one side of road = (1760 / 20) + 1
= 88 + 1
=89
? Trees on the both side = 2 x 89=178
Correct Answer: 1708249
Explanation:
1307 x 1307 = (1307)2
= (1300 + 7 )2
= (1300)2 + (7)2 + 2 x 1300 x 7
= 1690000 + 49 +18200
= 1708249
Correct Answer: 7 meter
Explanation:
? 2?R - 2?r = (176-132)
? 2?(R-r) = 44
? R-r = ( 44 x 7 )/ (2 x 22)
= 7 m
Correct Answer: 161 / 176
Explanation:
Given Exp. = (1/2 x 1/4 + 20) / (2 + 20) = (161/8) x (1/22)
= 161 / 176
Correct Answer: 4
Explanation:
NA
Correct Answer: 22/3
Explanation:
If the required fraction be P
According to the question
(P x P) / (1/P) = 1826/27
? P3 = 512/27
? P = 8/3 = 22/3
Correct Answer: 0.000064
Explanation:
(0.04)3 = 0.04 x 0.04 x 0.04
= 0.000064
Correct Answer: 0
Explanation:
We have p3 + q3 + r3 ? 3pqr = (p + q + r) (p2 + q2 + r2 ?pq ? qr - rp)
Here p = a ? 4, q = b ? 3, r = c ?1
So, given expression is (p + q + r) (p2 + q2 + r2 ? pq ? qr ? rp)
= (a ? 4 + b ? 3 + c ? 1) (p2 + q2 + r2 ? pq ? qr ? rp)
= (a + b + c ? 8) (p2 + q2 + r2 ? pq ? qr ? rp)
= (8 ? 8) (p2 + q2 + r2 ? pq ? qr ? rp)
? (a ? 4)3 + (b ? 3)3 + (c ? 1)3 ? 3 (a ? 4) (b ? 3) (c ? 1) = 0
Correct Answer: 2630
Explanation:
Let 3571 + x - 6086 = 115
Then, x = 6086 +115 -3571
= 6201-3571
= 2630
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