Difference between revisions of "2020 AMC 10B Problems/Problem 15"
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| − | Bash it out until you find a pattern. In the end, you'll see that the <math>2019^{th}</math>, <math>2020^{th}</math>, and the <math>2021^{st}</math> numbers are <math>2, 4, 5</math>, giving the answer <math>2+4+5= \boxed {D)11}</math> | + | Bash it out until you find a pattern. In the end, you'll see that the <math>2019^{th}</math>, <math>2020^{th}</math>, and the <math>2021^{st}</math> numbers are <math>2, 4, 5</math>, giving the answer <math>2+4+5= \boxed {\textbf{(D)} \text{ 11}}</math> |
~DragonWarrior123 | ~DragonWarrior123 | ||
Revision as of 20:05, 7 February 2020
Contents
Problem
Steve wrote the digits 
, 
, 
, 
, and 
in order repeatedly from left to right, forming a list of 
digits, beginning 
He then erased every third digit from his list (that is, the rd, 
th, 
th, 
digits from the left), then erased every fourth digit from the resulting list (that is, the th, 
th, 
th, digits from the left in what remained), and then erased every fifth digit from what remained at that point. What is the sum of the three digits that were then in the positions 
?
Solution
Bash it out until you find a pattern. In the end, you'll see that the 
, 
, and the 
numbers are 
, giving the answer 
~DragonWarrior123
Video Solution
~IceMatrix
See Also
| 2020 AMC 10B (Problems • Answer Key • Resources) | ||
| Preceded by Problem 14 |
Followed by Problem 16 | |
| 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 10 Problems and Solutions | ||
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. 
