Problem |
Hint |
1) A family has two children. At least one of them is a boy. What is the probability that both children are
boys?
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There are 4 possibilities of 2 children (G = girl and B = boy):
(G G)
(G B)
(B G)
(B B)
Probability of 2 boys = _____
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2) At the brand new middle school lockers open with PIN numbers instead of combination locks. PIN numbers consist of three one digit numbers and digits can repeat. This year all the 8th grade PIN numbers begin with the digits 6, 7, 8, or 9, but the other two can be any number from 0 up to 9. How big does the
8th grade class have to be to guarantee at least two students have the same PIN numbers?
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The number of possible PIN numbers is ______
So, with ______ students, the numbers begin to repeat.
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3)
Toni's teacher gives a 20 point quiz every Friday. On her first five quizzes Toni scores: 15, 4, 16, 18 , and
15. After the next two 20 point quizzes, her average on all seven quizzes is 15. What is the median?
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- Re-arrange the scores in numeric order:
    4 15 15 16 18
- The sum of these scores is ____
- For the mean to be 15 after 2 more scores, the sum must be
______
- Therefore, the next 2 added scores must sum to _____
- The possibilities for the last 2 scores are:
- With these added scores the median is _____
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