2007 UNCO Math Contest II Problems/Problem 5
Problem
Ten different playing cards have the numbers written on them as shown. Three cards are selected at random without replacement. What is the probability that the sum of the numbers on the three cards is divisible by ?
Solution
There are five ways to achieve a sum divisible by 7; 115 (2 ways), 133 ( 2 ways), 124 (8 ways), 233 (2 ways), 455 (2 ways). Hence, there are 16 favorable ways out of .
See Also
2007 UNCO Math Contest II (Problems • Answer Key • Resources) | ||
Preceded by Problem 4 |
Followed by Problem 6 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 | ||
All UNCO Math Contest Problems and Solutions |