Question
Question: Value of <sup>4</sup>C<sub>3</sub> + <sup>5</sup>C<sub>3</sub> + <sup>6</sup>C<sub>3</sub> ....... +...
Value of 4C3 + 5C3 + 6C3 ....... + 11C3 + 12C3 equal to
A
13C4 –1
B
13C4
C
13C4 + 1
D
12C4 – 1
Answer
13C4 –1
Explanation
Solution
Use nCr + nCr–1 = n+1Cr add subtract. 4C4