Which of these variables would MOST likely be examined through observational studies?

A) none of the variables
B) the economic output of a country
C) the speed at which a test object is released
D) the amount of current through an electric device

-3.5 degrees per hour

step-by-step explanation:

find the unit rate:

-12   1/4 degrees           12.25 degrees

= - = -3.5 degrees per hour

      3   1/2 hours               3.5 hours

1332.

this is because to get from 333 to 999 you multiply by 3, and you should do the same to the number of hours.

therefore you would do 444*3=1332

answer: chelsea has 55 brushes

step-by-step explanation:

5 x 11 = 55

5 + 55 = 60