If traveling at 80 km how long will it take to travel 20 km

I presume you mean 80 km per hour, which means that we divide 80 by 20 to get
4
which means that you can go 4 groups of 20 km in 1 hour. Therefore, it will take you 1/4 of an hour to go 20km

Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.

Answer// dinosaurs emerged during mesozoic era;