There are 10 children in a company's day-cre center, and a pair of children is to be selected to play a game. At most, how many different pairs are possible?
A)100
B)90
C)50
D)45
E)25
A)100
B)90
C)50
D)45
E)25
Number of ways to choose the 1st person: 10quitaskinme wrote:There are 10 children in a company's day-cre center, and a pair of children is to be selected to play a game. At most, how many different pairs are possible?
A)100
B)90
C)50
D)45
E)25
Number of ways to choose the 2nd person: 9
Total combinations = 10 x 9 = 90 if order matters
Since question asks for different pairs we have to remove the duplicates which is 1/2 of 90
90 - (0.5x90) = 45 or
90(1-1/2) = 90(0.5) = 90/2 = 45
Ans = d
