Four youngsters will be chosen from a group of six males and four girls. How many different ways can they be chosen to ensure that at least one boy is present?
A. 159
B. 194
C. 205
D. 209
Answer:D
Four youngsters will be chosen from a group of six males and four girls. How many different ways can they be chosen to ensure that at least one boy is present?
A. 159 B. 194 C. 205 D. 209
Explanation: We might have one boy and three girls, or two boys and two girls, or three boys and one female (4 boys).6C1 x 4C3) + (6C2 x 4C2) + (6C3 x 4C1) + (6C4) = (6C1 x 4C1) + (6C2 x 4C2) + (6C3 x 4C1) + (6C2) = (6 x 4) +6 x 5/2 x 1 x4 x 3/2 x 1 +6 x 5 x 4 x 4/ 3 x 2 x 1 2 x 1+6 =209.