Examveda

# In how many ways 2 students can be chosen from the class of 20 students?

A. 190

B. 180

C. 240

D. 390

\eqalign{ & { = ^{20}}{{\text{C}}_2} \cr & = \frac{{20!}}{{2! \times 18!}} \cr & = 20 \times \frac{{19}}{2} \cr & = 190 \cr}