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Iran MO (1st Round)
2018 Iran MO (1st Round)
8
8
Part of
2018 Iran MO (1st Round)
Problems
(1)
Tricky average problem - Iran First Round 2018, P8
Source:
3/7/2021
The license plate of each automobile in Iran consists of a two-digit and a three-digit number as well as a letter of the Persian alphabet. The digit
0
0
0
is not used in the two numbers. To each license plate, we assign the product of the two numbers on it. For example, if the two numbers are
12
12
12
and
365
365
365
on a license plate, the assigned number would be
12
×
365
=
4380
12 \times 365 = 4380
12
×
365
=
4380
. What is the average of all the assigned numbers to all possible license plates?
combinatorics