Skip to content / Đến nội dung
ThichHocToan.com

2015 AMC 12B Question 25

AMC12 · 2015 AMC 12B

Question 25

A bee starts flying from point $P_0.$ She flies $1$ inch due east to point $P_1.$ For $j \ge 1,$ once the bee reaches point $P_j,$ she turns $30^\circ$ counterclockwise and then flies $j + 1$ inches straight to point $P_{j+1}.$ When the bee reaches $P_{2015}$ she is exactly $a\sqrt b + c\sqrt d$ inches away from $P_0,$ where $a,$ $b,$ $c,$ and $d$ are positive integers and $b$ and $d$ are not divisible by the square of any prime. What is $a + b + c + d?$
  1. $2016$
  2. $2024$
  3. $2032$
  4. $2040$
  5. $2048$