A certain coin has a 0.65 probability of landing on heads. Which of the following expresses the
probability that the coin will land on heads at most 15 times in 25 flips?
(A) (
25
25
25
) (0.65)0 (0.35)25 + ( ) (0.65)1 (0.35)24 + ⋯ + ( ) (0.65)25 (0.35)0
0
25
1
(B) (
25
25
) (0.65)0 (0.35)15 + (25) (0.65)1 (0.35)14 + ⋯ + ( ) (0.65)15 (0.35)0
0
25
1
(C) (
15
15
) (0.65)0 (0.35)25 + (15) (0.65)1 (0.35)24 + ⋯ + ( ) (0.65)25 (0.35)0
0
15
1
(D) (
15
15
) (0.65)0 (0.35)15 + (15) (0.65)1 (0.35)14 + ⋯ + ( ) (0.65)15 (0.35)0
0
15
1
(E) (0.50)15 (1 − 0.50)10
Consider the first five rows of Pascal’s triangle.
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
Circle the exact location in the triangle where each of the following combinations is located.
•
•
•
•
•
The number of ways in which three cards can be selected out of four cards
The number of ways in which two cards can be selected out of three cards
The number of ways in which one card can be selected out of two cards
The number of ways in which zero cards can be selected out of four cards
The number of ways in which three cards can be selected out of three cards