WB JEE 2011 | Permutations and Combinations Question 7 | Mathematics

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WB JEE 2011

MCQ (Single Correct Answer)

-0.25

If $${}^n{C_4}$$, $${}^n{C_5}$$ and $${}^n{C_6}$$ are in A.P., then n is

7 or 14

14 or 21

WB JEE 2011

MCQ (Single Correct Answer)

-0.25

The number of diagonals in a polygon is 20. The number of sides of the polygon is

WB JEE 2011

MCQ (Single Correct Answer)

-0.25

$${}^{15}{C_3} + {}^{15}{C_5} + \,\,......\,\, + {}^{15}{C_{15}} = $$

$${2^{14}}$$

$${2^{14}} - 15$$

$${2^{14}} + 15$$

$${2^{14}} - 1$$

WB JEE 2012

MCQ (Single Correct Answer)

-0.33

A vehicle registration number consists of 2 letters of English alphabet followed by 4 digits, where the first digit is not zero. Then, the total number of vehicles with distinct registration numbers is

26² $$\times$$ 10⁴

$${}^{26}{P_2}$$ $$\times$$ $${}^{10}{P_4}$$

$${}^{26}{P_2}$$ $$\times$$ 9 $${}^{10}{P_3}$$

26² $$\times$$ 9 $$\times$$ 10³

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