Question

The number of $4$ letter code that can be formed by using the first $10$ letters of the English alphabet is $\alpha \beta \gamma \delta .$ If no letter is repeated, then

• A. $\alpha +\beta +\gamma +\delta =10$
• B. $\alpha +\beta +\gamma +\delta =9$
• C. $\alpha \times \gamma =20$
• D. $\alpha \times \beta =0$

Answer 1

Answer: (B), (C), (D)

$\alpha \times \beta =0$

We need to form a $4$ digit code using $10$ alphabets
So, the total possible ways
$=10\times 9\times 8\times 7=5040$
$\therefore \alpha =5,\beta =0,\gamma =4,\delta =0$