Answer:
Step-by-step explanation:
[logical equivalence]
[morgan laws]
if
is true, then
is true and
is too.
with
true, then
is false [double denial]
In the first equivalence it follows that
is true [identity law]
Then it can be concluded that 
21 of the squares are shaded in
Answer:
two hundred seventy four thousand seventy-five
We have the following given
mileage = 70 miles per gallon
distance = 60 km
Required: amount of fuel in gallons
First, we must convert the distance to miles, so
60 km (1 mi/1.6 km) = 37.5 mi
So, the amount of fuel is
37.5 mi / (70 mi/gal) = 0.54 gallons
Clockwise 90 is the same as counterclockwise 270. Since 270+90=360, going 270 degrees one way is the same as going 90 degrees the other way.