diff --git a/3-limit-service-time/main.go b/3-limit-service-time/main.go
index 6a0ebb3..4899078 100644
--- a/3-limit-service-time/main.go
+++ b/3-limit-service-time/main.go
@@ -10,19 +10,47 @@
 
 package main
 
+import (
+	"sync"
+	"time"
+)
+
+const MAX_SECONDS = 10
+
 // User defines the UserModel. Use this to check whether a User is a
 // Premium user or not
 type User struct {
 	ID        int
 	IsPremium bool
 	TimeUsed  int64 // in seconds
+	mu        sync.Mutex
 }
 
 // HandleRequest runs the processes requested by users. Returns false
 // if process had to be killed
 func HandleRequest(process func(), u *User) bool {
-	process()
-	return true
+	finished := make(chan bool)
+
+	// unfortunately we won't be able to kill the goroutine.
+	// So a call to process() may exceeds MAX_SECONDS duration.
+	go func() {
+		process()
+		finished <- true
+	}()
+
+	select {
+	case <-finished:
+		return true
+	case <-time.After(MAX_SECONDS * time.Second):
+		if u.IsPremium {
+			<-finished
+			return true
+		}
+		u.mu.Lock()
+		u.TimeUsed += MAX_SECONDS
+		u.mu.Unlock()
+		return false
+	}
 }
 
 func main() {