task 30

Author: BEPb

tasks/99.md tasks/41.mdtasks/99.md renamed to tasks/41.md

@@ -1,6 +1,6 @@
 ### 
 
-<img src="./art/99.png" alt="solution" >
+<img src="./art/41.png" alt="solution" >
 
 #### eng:
 

tasks/41.sql

@@ -0,0 +1,26 @@
+### 
+
+<img src="./art/42.png" alt="solution" >
+
+#### eng:
+
+
+
+#### рус:
+
+
+
+#### код с коментариями:
+```sql
+
+```
+
+#### код для hackerrank:
+```sql
+
+```
+
+
+#### На [главную](https://github.com/BEPb/hackerrank_sql#readme)
+
+---

tasks/42.md

@@ -0,0 +1,26 @@
+### 
+
+<img src="./art/43.png" alt="solution" >
+
+#### eng:
+
+
+
+#### рус:
+
+
+
+#### код с коментариями:
+```sql
+
+```
+
+#### код для hackerrank:
+```sql
+
+```
+
+
+#### На [главную](https://github.com/BEPb/hackerrank_sql#readme)
+
+---

tasks/42.sql

@@ -0,0 +1,26 @@
+### 
+
+<img src="./art/44.png" alt="solution" >
+
+#### eng:
+
+
+
+#### рус:
+
+
+
+#### код с коментариями:
+```sql
+
+```
+
+#### код для hackerrank:
+```sql
+
+```
+
+
+#### На [главную](https://github.com/BEPb/hackerrank_sql#readme)
+
+---

tasks/43.md

@@ -0,0 +1,26 @@
+### 
+
+<img src="./art/40.png" alt="solution" >
+
+#### eng:
+
+
+
+#### рус:
+
+
+
+#### код с коментариями:
+```sql
+
+```
+
+#### код для hackerrank:
+```sql
+
+```
+
+
+#### На [главную](https://github.com/BEPb/hackerrank_sql#readme)
+
+---