- Consider the following arrangements of numbers:
2, 6, 7, 5, 4, 3, 7, 4, 8, 9, 4, 8, 9, 4, 3, 2, 5, 4, 7, 9, 8, 6, 8, 7, 1, 2, 5, 3, 7, 6, 8, 9, 3, 6
How many 7’s are there in the above series which are immediately preceded by an even number and immediately followed by an odd number? NUMBER ARRANGEMENT
(1) 2
(2) 4
(3) 3
(4) 5
EXPLANATION
We’ll go through the series and identify instances where 7 is preceded by an even number and followed by an odd number:
- 6,7,56,7,5 (7 is preceded by 6 and followed by 5)
- 4,7,44,7,4 (7 is preceded by 4 and followed by 4)
- 8,7,18,7,1 (7 is preceded by 8 and followed by 1)
- 6,7,96,7,9 (7 is preceded by 6 and followed by 9)
- 8,7,18,7,1 (7 is preceded by 8 and followed by 1)
So, there are 5 instances where 7 is immediately preceded by an even number and immediately followed by an odd number.
Therefore, the answer is: (4) 5
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