MathematicsEasy64×since 2002Q2998If 20Cr{{}^{20}{C_r}}20Cr is the co-efficient of x^r in the expansion of (1 + x)²⁰, then the value of ∑r=020r2.20Cr\sum\limits_{r = 0}^{20} {{r^2}.{}^{20}{C_r}}r=0∑20r2.20Cr is equal to :A420×219420 \times {2^{19}}420×219B380×219380 \times {2^{19}}380×219C380×218380 \times {2^{18}}380×218D420×218420 \times {2^{18}}420×218Check answerSkip