Number System
- The number 323 has
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323 = 17 × 19
Correct Option: C
323 = 17 × 19
- 252 m of pant cloth and 141 m of shirt cloth are available in a cloth store. To stitch one pant and one shirt,
m of cloth are needed respectively. Then the approximate number of pants and shirts that can be made out of it are2 1 m and 1 3 2 4
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Number of pants
= 252 2 1 2 = 252 × 2 = 100 5
Number of shirts= 141 × 4 ≈ 100 7 Correct Option: B
Number of pants
= 252 2 1 2 = 252 × 2 = 100 5
Number of shirts= 141 × 4 ≈ 100 7
- There are 50 boxes and 50 persons. Person 1 keeps 1 marble in every box. Person 2 keeps 2 marbles in every 2nd box, person 3 keeps 3 marbles in every third box. This process goes on till person 50 keeps 50 marbles in the 50th box. Find the total
number of marbles kept in the 50th box.
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Marbles in the 50th box will be kept by 1st, 2nd, 5th, 10th, 25th and 50th persons.
[There are the factors of 50].
∴ Number of marbles
= 1 + 2 + 5 + 10 + 25 + 50 = 93Correct Option: D
Marbles in the 50th box will be kept by 1st, 2nd, 5th, 10th, 25th and 50th persons.
[There are the factors of 50].
∴ Number of marbles
= 1 + 2 + 5 + 10 + 25 + 50 = 93
- The value of
999 95 × 99 is 99
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Expression
= 
99 + 95 
× 99 99
= 99 × 99 + 95
= 99(100 – 1) + 95
=9900 – 99 + 95 = 9896Correct Option: D
Expression
= 99 + 95 × 99 99
= 99 × 99 + 95
= 99(100 – 1) + 95
=9900 – 99 + 95 = 9896
- The sum of a two digit number and the number obtained by reversing its digits is a square number. How many such numbers are there ?
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If the number be 10x + y then number obtained by reversing the digits = 10y + x.
∴ 10x + y + 10y + x = 11 (x + y)
If x + y = 11 the possible pairs are= (2, 9), (3, 8), (4, 7) and (5, 6)
∴ Required answer = 8Correct Option: D
If the number be 10x + y then number obtained by reversing the digits = 10y + x.
∴ 10x + y + 10y + x = 11 (x + y)
If x + y = 11 the possible pairs are= (2, 9), (3, 8), (4, 7) and (5, 6)
∴ Required answer = 8
