Question

Tara's car accelerated from 10 miles per hour to 70 miles per hour in 12 seconds.

Answer 1

Acceleration=change in velocity/time
a=(70-10)/12
a=60/12
a=5
So it is A

Hope this helps :)

Answer 2

Rate of change is very similar to slope.
It is the increase in y's/increase in x's.
It took the car 12 second to increase from 10 mph to 70 mph. This is an increase of 60 mph in 12 seconds.
So the rate of change would be 60 mph/12 sec or 5 mph per sec (A)