How do I plan to run Setia Eco this Saturday

The goal is to finish within 3 hours.

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So thinking of 7:45 minutes pace for first 10km.

Then 8:00 minutes for the next 10km pace.

then I got left 15 minutes for me to walk to the finish line..

hopefully my garmin will got get cranky this Saturday.

I have lotsa watches already..dont need an extra one.. :p