Answer:
Tuesday
Step-by-step explanation:
Days of the week repeat every seven days, so Saturday is day (1+7n) for some integer n.
Number of weeks
The value of n that makes the day number just under 10,000 is ...
1 +7n ≤ 10000
7n ≤ 9999
n ≤ 1428 3/7
Day of the week
So, Day 1 +1428·7 = 9997 is Saturday. Day 10,000 is 3 days later. That makes Day 10,000 a Tuesday.
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Additional comment
1428 weeks is about 27.5 years. You got married at age 27.
