Number Series Questions For Railway Group-D PDF:
Download Number Series Questions For Railway Group-D PDF with detailed solutions. Important Practice Ratio and Proportion questions based on previous year railway exam papers.
Download Number Series Questions For Railway Group-D PDF
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Question 1: Identify the wrong number in the following series–
216, 163, 120, 72, 24
a) 216
b) 163
c) 72
d) 214
Question 2: 5 pencils and 4 erasers cost Rs 13 whereas 9 pencils and 5 erasers cost Rs 19 Then the price of 6 pencils and 3 erasers is
a) Rs 9
b) Rs 12
c) Rs 15
d) Rs 18
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Question 3: Consider the natural numbers 88935. Then the least natural number by which we can divide or multiply the number to make it a square number is
a) 3
b) 5
c) 15
d) None of these
Question 4: The number of four-digit number greater than or equal to 4321 that can be formed from the digit 0,1,2,3,4,5 allowing for repetition of digits is
a) 360
b) 310
c) 313
d) 311
Question 5: 42 : 56 : : 72 : ?
a) 96
b) 92
c) 100
d) 51
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Answers & Solutions:
1) Answer (B)
The series from the right is 24 x 1, 24 x 3, 24 x 5, 24 x 7 and 24 x 9.
For example,
24 x 1 = 24
24 x 3 = 72
24 x 5 = 120
24 x 7 = 168
24 x 9 = 216
So, the wrong number is 163. The correct number is 24 x 7 = 168
2) Answer (B)
5p + 4e = 13
9p + 5e = 19
solving for p, we get p = 1
e = 2
So, 6 pencils and 3 erasers cost
6 x 1 + 3 x 2 = 12
3) Answer (C)
88935 can be written as 5929 x 15
5929 is the square of 77
So, the answer is 15
4) Answer (D)
If the number is in 5 thousands, there are 6x6x6 ways of choosing it.
If the number is in 4 thousands 4 hundreds there are 2x6x6 ways of choosing it.
If the number is in 4 thousand 3 hundreds, there are 3 x 6 + 5 ways of choosing it.
So, total ways = 6x6x6 + 2x6x6 + 3×6 + 5 = 311
5) Answer (A)
14 x 3 = 42
14 x 4 = 56
Likewise
24 x 3 = 72
24 x 4 = 96
