2024 AMC 8 Problems/Problem 8

Revision as of 15:59, 25 January 2024 by Mathperson12321 (talk | contribs) (Problem)

Problem

On Monday Taye has $2. Every day, he either gains $3 or doubles the amount of money he had on the previous day. How many different dollar amounts could Taye have on Thursday, 3 days later?

$\textbf{(A) } 3\qquad\textbf{(B) } 4\qquad\textbf{(C) } 5\qquad\textbf{(D) } 6\qquad\textbf{(E) } 7$

==Solution 1== (BRUTE FORCE) How many values could be on the first day? Only $2$ dollars. The second day, you can either add $3$ dollars, or double, so you can have $5$ dollars, or $4$. For each of these values, you have $2$ values for each. For $5$ dollars, you have $10$ dollars or $8$, and for $4$ dollars, you have $8$ dollars or $7$. Now, you have $2$ values for each of these. For $10$ dollars, you have $13$ dollars or $20$, for $8$ dollars, you have $16$ dollars or $11, for$8$dollars, you have$16$dollars or$11$, and for$7$dollars, you have$14$dollars or$10$.${$11}$ (Error compiling LaTeX. Unknown error_msg),${$ (Error compiling LaTeX. Unknown error_msg)16}$repeat leaving you with$8-2 = \boxed{(C) 6}$ different values

Video Solution 1(easy to digest) by Power Solve

https://youtu.be/16YYti_pDUg?si=5kw0dc_bZwASNiWm&t=121