2016 AMC 12B Problem 7


Josh writes the numbers 1,2,3,,99,1001,2,3,\ldots,99,100 . He marks out 11 , skips the next number (2)(2) , marks out 33 , and continues skipping and marking out the next number to the end of the list. Then he goes back to the start of his list, marks out the first remaining number (2)(2) , skips the next number (4)(4) , marks out 66 , skips 88 , marks out 1010 , and so on to the end. Josh continues in this manner until only one number remains. What is that number?

(A) 13(B) 32(C) 56(D) 64(E) 96\textbf{(A)}\ 13 \qquad\textbf{(B)}\ 32 \qquad\textbf{(C)}\ 56 \qquad\textbf{(D)}\ 64 \qquad\textbf{(E)}\ 96


Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.

Show/Hide Hints

Show/Hide Problem Tags

Problem Tags: Counting and probability

Want to contribute problems and receive full credit? Click here to add your problem!
Please report any issues to us in our Discord server
Go to previous contest problem (SHIFT + Left Arrow) Go to next contest problem (SHIFT + Right Arrow)
Category: AMC 12B
Points: 2
Back to practice