Answer:
60m/s
Step-by-step explanation:
velocity of the while moving is 30 m/s and it becomes 90 m/s after speeding up at constant rate. so the average velocity of the journey is
[90+30] /2
=60 m/s
40 tens is another way of writing 4 hundreds because 40 tens would give you 400 and 4 hundreds also give you 400.
Parameterize this surface (call it
) by

with
and
. The limits on
should be obvious. We find the upper limit for
by solving for
where the sphere and cone intersect:




Take the normal vector to
to be

(orientation does not matter here)
Then the area of
is



4 $700 apartments for 2,800 and 2 $900 apartments for 1,800...2800+1800=4,600