diff --git a/erase-jeong/README.md b/erase-jeong/README.md
index aa29d04..0c848ff 100644
--- a/erase-jeong/README.md
+++ b/erase-jeong/README.md
@@ -5,4 +5,7 @@
 | 1차시 | 2023.03.18 |  그리디  |  [구명보트](https://school.programmers.co.kr/learn/courses/30/lessons/42885)  | [#1](https://github.com/AlgoLeadMe/AlgoLeadMe-9/pull/4)|
 | 2차시 | 2023.03.23 |  DFS/BFS  |  [촌수계산](https://www.acmicpc.net/problem/2644)  | [#2](https://github.com/AlgoLeadMe/AlgoLeadMe-9/pull/8)|
 | 3차시 | 2023.03.28 |  DP  |  [평범한 배낭](https://www.acmicpc.net/problem/12865)  | [#3](https://github.com/AlgoLeadMe/AlgoLeadMe-9/pull/12)|
-| 4차시 | 2023.03.28 |  DP  |  [미로 탐색](https://www.acmicpc.net/problem/2178)  | [#4](https://github.com/AlgoLeadMe/AlgoLeadMe-9/pull/17)|
+| 4차시 | 2023.04.05 |  DP  |  [미로 탐색](https://www.acmicpc.net/problem/2178)  | [#4](https://github.com/AlgoLeadMe/AlgoLeadMe-9/pull/17)|
+| 5차시 | 2023.04.15 |  구현  |  [기능개발](https://school.programmers.co.kr/learn/courses/30/lessons/42586)  | [#5](https://github.com/AlgoLeadMe/AlgoLeadMe-9/pull/18)|
+---
+
diff --git "a/erase-jeong/\352\265\254\355\230\204/\352\270\260\353\212\245\352\260\234\353\260\234.py" "b/erase-jeong/\352\265\254\355\230\204/\352\270\260\353\212\245\352\260\234\353\260\234.py"
new file mode 100644
index 0000000..237e0d5
--- /dev/null
+++ "b/erase-jeong/\352\265\254\355\230\204/\352\270\260\353\212\245\352\260\234\353\260\234.py"
@@ -0,0 +1,41 @@
+def solution(progresses,speeds):
+    devTime=[]
+    answer=[]
+    count=0
+
+    for i in range(len(progresses)):
+        time=(100-progresses[i])/speeds[i]
+        if time%1!=0:
+            print("time : ", time)
+            time=time//1+1
+            
+
+        devTime.append(int(time))
+
+    #print(devTime)
+    tmp=devTime[0]
+
+    for i in range(1,len(devTime)):
+        if tmp<devTime[i]:
+            count+=1
+            answer.append(count)
+            count=0
+            tmp=devTime[i]
+        else:
+            count+=1
+
+        if i==len(devTime)-1:
+            answer.append(count+1)
+
+    return answer
+
+
+##test 1
+#progresses=[93,30,55]
+#speeds=[1,30,5]
+
+##test 2
+#progresses=[95,90,99,99,80,99]
+#speeds=[1,1,1,1,1,1]
+
+#print(solution(progresses,speeds))
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