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Zorluk: OrtaBasic Probability and Counting Methods

A fair spinner is divided into 88 congruent sectors numbered 11 through 88. A player spins the spinner twice in succession. How many of the 6464 possible outcomes result in a sum of the two spins that is strictly greater than 1212?

Cevap: 10 outcomes

Cevap

There are 10 outcomes that yield a sum strictly greater than 12.
Systematically listing all ordered pairs (x,y)(x, y) from {1,2,,8}×{1,2,,8}\{1, 2, \dots, 8\} \times \{1, 2, \dots, 8\} such that x+y>12x + y > 12 yields 4 outcomes for sum 13, 3 outcomes for sum 14, 2 outcomes for sum 15, and 1 outcome for sum 16, totaling 10 valid outcomes.

Adım Adım Çözüm

1
Determine the acceptable sums for the two spins
The possible sums strictly greater than 12 are 13, 14, 15, and 16.
Since each spin has a maximum value of 8, the maximum possible sum is 8 + 8 = 16.
2
Count the ordered pairs (spin 1, spin 2) for each valid sum
4 outcomes for sum 13, 3 outcomes for sum 14, 2 outcomes for sum 15, and 1 outcome for sum 16.
First and second spins are ordered, so (5,8) and (8,5) represent distinct outcomes.
3
Sum the outcome counts across all valid cases
4 + 3 + 2 + 1 = 10 outcomes.
The sets of outcomes for distinct sums are mutually exclusive.

Anahtar Kavram

Basic Probability and Counting Sample Space Outcomes
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