MathematicsEasy64×since 2002Q2990The value of ∑r=02050−rC6\sum\limits_{r = 0}^{20} {{}^{50 - r}{C_6}}r=0∑2050−rC6 is equal to:A50C6−30C6{}^{50}{C_6} - {}^{30}{C_6}50C6−30C6B51C7−30C7{}^{51}{C_7} - {}^{30}{C_7}51C7−30C7C50C7−30C7{}^{50}{C_7} - {}^{30}{C_7}50C7−30C7D51C7+30C7{}^{51}{C_7} + {}^{30}{C_7}51C7+30C7Check answerSkip