diff --git "a/_WeeklyChallenges/W20-[TwoPointer]/Assignment_BOJ_2473_\354\204\270 \354\232\251\354\225\241.py" "b/_WeeklyChallenges/W20-[TwoPointer]/Assignment_BOJ_2473_\354\204\270 \354\232\251\354\225\241.py"
new file mode 100644
index 0000000..4510a53
--- /dev/null
+++ "b/_WeeklyChallenges/W20-[TwoPointer]/Assignment_BOJ_2473_\354\204\270 \354\232\251\354\225\241.py"	
@@ -0,0 +1,20 @@
+N = int(input())
+sol = list(map(int, input().split()))
+sol.sort()
+
+result = [1000000000, 1000000000, 1000000000]
+for k in range(N):
+    i = k + 1
+    j = N - 1
+    while i < j:
+        if abs(sol[i] + sol[j] + sol[k]) < abs(sum(result)):
+            result = [sol[k], sol[i], sol[j]]
+
+        if sol[i] + sol[j] + sol[k] > 0:
+            j -= 1
+        elif sol[i] + sol[j] + sol[k] < 0:
+            i += 1
+        else:
+            break
+
+print(*result)
\ No newline at end of file
diff --git a/_WeeklyChallenges/W20-[TwoPointer]/README.md b/_WeeklyChallenges/W20-[TwoPointer]/README.md
new file mode 100644
index 0000000..eadfb54
--- /dev/null
+++ b/_WeeklyChallenges/W20-[TwoPointer]/README.md
@@ -0,0 +1,17 @@
+## 🚀4월 3주차 (4/21) 스터디 발제 주제: Two Pointer, Binary Search
+> 발제자: 조윤상 (@YoonYn9915)
+
+> [!NOTE]
+> 주제: Two Pointer, Binary Search
+
+### 🗂️ 스터디 자료
+- PDF: [바로가기
+](Study_BOJ_2240.pdf)
+
+### 📖 문제
+- [백준 #2240. 두 용액](https://www.acmicpc.net/problem/2240): Two Pointer, Binary Search / 골드 5
+- 정답 코드: [Study_BOJ_2240_두 용액.py](Study_BOJ_1759_암호만들기.py)
+
+### 💻 과제
+- [백준 #2473. 세 용액](https://www.acmicpc.net/problem/2473): Two Pointer, Binary Search / 골드 3
+- 정답 코드: [Assignment_BOJ_2473_세 용액.py](Assignment_BOJ_2473_세 용액.py)
diff --git a/_WeeklyChallenges/W20-[TwoPointer]/Study_BOJ_2240.pdf b/_WeeklyChallenges/W20-[TwoPointer]/Study_BOJ_2240.pdf
new file mode 100644
index 0000000..42ca8fd
Binary files /dev/null and b/_WeeklyChallenges/W20-[TwoPointer]/Study_BOJ_2240.pdf differ
diff --git "a/_WeeklyChallenges/W20-[TwoPointer]/Study_BOJ_2470_\353\221\220 \354\232\251\354\225\241.py" "b/_WeeklyChallenges/W20-[TwoPointer]/Study_BOJ_2470_\353\221\220 \354\232\251\354\225\241.py"
new file mode 100644
index 0000000..7b3c625
--- /dev/null
+++ "b/_WeeklyChallenges/W20-[TwoPointer]/Study_BOJ_2470_\353\221\220 \354\232\251\354\225\241.py"	
@@ -0,0 +1,27 @@
+import sys
+
+N = int(sys.stdin.readline())
+arr = sorted(map(int, sys.stdin.readline().split()))
+
+left = 0
+right = N - 1
+
+answer = (arr[left], arr[right], abs(arr[left] + arr[right]))
+
+# 투 포인터 사용해서 절대값이 0에 가장 가까운 두 값 찾기
+while left < right:
+    total = arr[left] + arr[right]
+    abs_total = abs(total)
+
+    if abs_total < answer[2]:
+        answer = (arr[left], arr[right], abs_total)
+        if abs_total == 0:
+            break
+    # 두 용액의 값이 0보다 크면 right를 줄여서 합을 작게 만든다
+    if total > 0:
+        right -= 1
+    else:
+        # 두 용액의 값이 0보다 작으면 left를 늘려서 합을 크게 만든다
+        left += 1
+
+print(f"{answer[0]} {answer[1]}")
\ No newline at end of file