When darcy's school bus travels at 30 miles per hour, it gets from her home to school in 12 minutes. what is the speed of darcy's bus if it makes the same trip in 18 minutes?

We know that
speed=distance/time> distance=speed*time

step 1
find the distance with
speed=30 miles/hour> 30 miles/60 minutes> 0.5 miles/minute
time=12 minutes
distance=speed*time> distance=0.5/12> distance=6 miles

the distance from home to school is 6 miles

step 2
find the speed with
distance=6 miles
time=18 minutes
speed=6/18> 0.33 miles/minute> *60> 20 miles/hour

the answer is
20 miles/hour  or 0.33 miles/minutes

The following which is not a characteristics of a point is:

                       Flat surface.

Step-by-step explanation:

Point--

In three dimensional geometry(i.e. 3-D) a point is a just a location.It is one of the undefined term of geometry.

( The other undefined terms of geometry is:

          Line and a Plane)

It is denoted by a symbol: A letter in capitals.It has no dimension i.e. it neither has a length,nor width nor height.

         Hence, the answer is: Flat surface