Restart the thread when two threads are running simultaneously in c#

Question

Hi , I need some help in below scenerio.

I have 2 task which are running parallel where some operations are going on where 1st Task is completing in 5 min and in 2nd monthd its taking to complete around hrs.

Task.Run ( async()=> {  await oneMethod()}) ; 

Task.Run ( async()=> {  await SecondMethod()}) ; 

Now, I just wanna to execute first Task.Run when 2nd task is taking more than 15 min.

how to do that