September badge challenge: Earn either the Artificial Intelligence Basics badge or the IoT Basics badge before October 10th for a chance to win an Apple Watch Sport. I have completed this challenge, now what to do after completing this challenge.

I want to create a Time-dependent workflow rule on Account object and this workflow should fire/run after 15 minutes of record's creation.

I try for this but when we used to give time for workflow trigger it does not give/support option to enter minutes, please help me how can i achive it?

Note: For this i do not want to use batch class.

Any idea, if any one have share it.