एक (4)-अक्षरी शब्द-संकेत में (8) अक्षरों में से अक्षर चुने जाते हैं। पहला और दूसरा अक्षर अलग हों, तीसरा पहले जैसा हो और चौथा दूसरे जैसा न हो। कुल कितने संकेत बनेंगे?
In a (4)-letter word signal, letters are chosen from (8) letters. The first and second letters must be different, the third must be the same as the first, and the fourth must not be the same as the second. How many signals are possible?
Explanation opens after your attempt
A. \(8 \times 7 \times 1 \times 7=392\)
Concept
The third position is forced by the first letter, so it has (1) choice, and the fourth has (7) choices excluding the second letter. Count forced positions separately.
Why this answer is correct
The correct answer is A. \(8 \times 7 \times 1 \times 7=392\). The third position is forced by the first letter, so it has (1) choice, and the fourth has (7) choices excluding the second letter. Count forced positions separately.
Exam Tip
तीसरे स्थान पर पहले अक्षर की बाध्यता से (1) विकल्प है और चौथे पर दूसरे अक्षर को छोड़कर (7) विकल्प हैं। बाध्य स्थानों को अलग से गिनें।
Login to save your score, XP, coins and progress.