Hardest math question

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Avatar of anniewang9389

 Give a hard math question,whoever gives the hardest wins 1 pi.

Avatar of youblundered_XD

Tell the ones place digit of the answer in 47^2020 (47 to the power 2020)

Avatar of BishopTurtle
youblundered_XD wrote:

Tell the ones place digit of the answer in 47^2020 (47 to the power 2020)

The ones digits go in repeating sets of four: 7, 9, 3, 1, and since 2020 = 0 (mod 4), then the ones place of 47^2020 would be 1.

Avatar of 1e41-O

This one stumped me during the amc10b

Bela and Jenn play the following game on the closed interval $[0, n]$ of the real number line, where $n$ is a fixed integer greater than $4$. They take turns playing, with Bela going first. At his first turn, Bela chooses any real number in the interval $[0, n]$. Thereafter, the player whose turn it is chooses a real number that is more than one unit away from all numbers previously chosen by either player. A player unable to choose such a number loses. Using optimal strategy, which player will win the game?

$\textbf{(A)} \text{ Bela will always win.} \qquad \textbf{(B)} \text{ Jenn will always win.} \qquad \textbf{(C)} \text{ Bela will win if and only if }n \text{ is odd.}$ $\textbf{(D)} \text{ Jenn will win if and only if }n \text{ is odd.} \qquad \textbf{(E)} \text { Jenn will win if and only if } n>8.$

Avatar of JHQ18

Diffy Q's or Abstract Geometry problem ???

 

Avatar of SciFiChess

Before looking up the official solution, this is what I came up with for Problem 16 on the 2020 AMC 10B, which was posted by @1e41-O in comment #4.

(A) Bela [the first player] will always win.

The first player starts by selecting n/2 as the first choice. If the second player chooses x on any turn, then the first player chooses n-x on the next turn.

Note that you can generalize the problem and let n be any positive real number. The players still play on the interval [0,n] and all other rules remain the same. The first player will still win using the same strategy.

This is the link to the problem and official solution.

2020 AMC 10B Problem 16