2015 AMC 12B Problems/Problem 6
Problem
Back in 1930, Tillie had to memorize her multiplication facts from to
. The multiplication table she was given had rows and columns labeled with the factors, and the products formed the body of the table. To the nearest hundredth, what fraction of the numbers in the body of the table are odd?
Solution
There are a total of products, and a product is odd if and only if both its factors are odd. There are
odd numbers between
and
, namely
hence the number of odd products is
. Therefore the answer is
.
See Also
2015 AMC 12B (Problems • Answer Key • Resources) | |
Preceded by Problem 5 |
Followed by Problem 7 |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | |
All AMC 12 Problems and Solutions |
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