The probability expression is [tex]\frac{^{6}C_2}{^{20}C_2}[/tex]
The given parameters are
The total number of people is
n = 20
2 of the 20 people are to be selected.
So, the number of selection is
[tex]n = ^nC_r[/tex]
This gives
[tex]n = ^{20}C_2[/tex]
The expression that represents both students being sophomore is
[tex]n = ^{6}C_2[/tex] --- i.e. 2 students selected from 6
The probability is then represented as:
[tex]\frac{^{6}C_2}{^{20}C_2}[/tex]
Hence, the probability expression is [tex]\frac{^{6}C_2}{^{20}C_2}[/tex]
Read more about probability at:
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