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AP EAMCET · Maths · Binomial Theorem

\({ }^{37} C_4+\sum_{r=1}^5(42-r)_{C_r}=\)

  1. A \({ }^{41} C_4\)
  2. B \({ }^{39} C_4\)
  3. C \({ }^{38} C_4\)
  4. D \({ }^{42} C_4\)
Verified Solution

Answer & Solution

Correct Answer

(D) \({ }^{42} C_4\)

Step-by-step Solution

Detailed explanation

Given that, \[ \begin{aligned} & { }^{37} C_4+\sum_{r=1}^5{ }^{(42-r)} C_r \\ & ={ }^{37} C_4+{ }^{41} C_1+{ }^{40} C_2+{ }^{39} C_3+{ }^{38} C_3+{ }^{37} C_3 \\ & ={ }^{37} C_3+{ }^{37} C_4+{ }^{38} C_3+{ }^{39} C_3+{ }^{40} C_3+{ }^{41} C_3 \end{aligned} \] As we know,…