अनुक्रम 1, 5, 7, 3, 5, 7, 4, 3, 5, 7 में, ऐसे कितने 5 हैं जिनके ठीक पहले 3 नहीं है किन्तु ठीक बाद 7 है?
सही उत्तर: (A) 1
दी गई श्रृंखला 1, 5, 7, 3, 5, 7, 4, 3, 5, 7 में ऐसे 5 की पहचान करनी है जिसके पहले 3 न हो लेकिन बाद में 7 हो: पहले 5 (1, 5, 7) के पहले 1 और बाद में 7 है (मान्य); दूसरे 5 (3, 5, 7) के पहले 3 है (अमान्य); तीसरे 5 (3, 5, 7) के पहले भी 3 है (अमान्य)। अतः ऐसी स्थिति केवल 1 बार आती है।
In English (Question & Model Answer)
In the sequence 1, 5, 7, 3, 5, 7, 4, 3, 5, 7, how many such 5s are there which are not immediately preceded by 3 but are immediately followed by 7?
Correct Answer: (A) 1
In the sequence 1, 5, 7, 3, 5, 7, 4, 3, 5, 7, we inspect each occurrence of 5 for being not preceded by 3 and followed by 7: the first 5 (in 1, 5, 7) is preceded by 1 and followed by 7 (valid); the second 5 (in 3, 5, 7) is preceded by 3 (invalid); the third 5 (in 3, 5, 7) is also preceded by 3 (invalid). Thus, there is exactly 1 valid occurrence.