Binomial Theorem And Its Simple Applications Question 5

Question: The value of $\begin{aligned} & \left({ }^{10} C_0\right)+\left({ }^{10} C_0+{ }^{10} C_1\right)+\left({ }^{10} C_0+{ }^{10} C_1 +{ }^{10} C_2\right)+\ldots \ldots+\left({ }^{10} C_0+{ }^{10} C_1 { }^{10} C_2+\ldots+{ }^{10} C_9\right) \text { is }\end{aligned}$

Options:

A) $ 2^{10} $

B) $ {{10.2}^{9}} $

C) $ {{10.2}^{10}} $

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

  • [b] $ {{(}^{10}}C_0)+{{(}^{10}}C_0+{{}^{10}}C_1)+{{(}^{10}}C_0+{{}^{10}}C_1+{{}^{10}}C_2) $

$ +….+{{(}^{10}}C_0+{{}^{10}}C_1+{{}^{10}}C_2+…+{{}^{10}}C_9) $

$ =10{{}^{10}}C_0+9{{}^{10}}C_1+8{{}^{10}}C_2+…+{{}^{10}}C_9 $

$ ={{}^{10}}C_1+2{{}^{10}}C_2+3{{}^{10}}C_3+…10{{}^{10}}C_{10} $

$ =\sum\limits_{r=1}^{10}{r^{10}C_{r}=10\sum\limits_{r=1}^{10}{^{9}{C_{r-1}}={{10.2}^{9}}}} $