7
practice examMultiple Choice

Practice Exam

Question 7 • Grade 7 Mathematics

Maggie’s bank has assigned her a temporary 3 -digit PIN to use with her ATM card. Each digit is a number from 1 to 5 , inclusive, and no digit can be used more than once in the PIN. Which multiplication problem can be used to determine the probability that the PIN she was assigned was 123 ?

Answer
A
1 fifth times 1 fifth times 1 fifth
B
1 fifth times 1 fourth times 1 third
C
4 fifths times 4 fifths times 4 fifths
D
4 fifths times 3 fourths times 2 thirds

Explanation

There are 5 possible digits for the first position, then 4 remaining digits for the second, and 3 for the third because digits cannot repeat. For the specific PIN 123, the chances of getting each required digit in order are 1/5, then 1/4, then 1/3. Multiplying these probabilities gives choice B: 1 fifth times 1 fourth times 1 third.

AI-written and checked against the verified answer.

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