If the ratio of students with green shirts to total students in a class is 3 to 8, and are 12 students wearing green shirts, how many are there without green shirts?

20

Explanation:

You would set up a proportion in order to solve this

3 green           12 green

    =  

8 total                x total

Then you would cross mulitply for x and get 32. Since that is the total number, you would have to subract the 12 from 32 to get 20.

light-year  

the distance that light travels in a vacuum in one year, equal to about 9.46 trillion km (5.88 trillion mi). light-years are used in measuring interstellar and intergalactic distances.  

parsec  

a unit of distance used in astronomy, equal to about 3.25 light years (3.08 × 1016 meters).  

parallax  

the apparent angular displacement of a celestial body due to its being observed from the surface instead of from the center of the earth (diurnal parallax or geocentric parallax) or due to its being observed from the earth instead of from the sun (annual parallax or heliocentric parallax)  

absolute magnitude  

the magnitude (brightness) of a celestial object as it would be seen at a standard distance of 10 parsecs.  

apparent magnitude  

the magnitude of a celestial object as it is actually measured from the earth.  

redshift  

an increase in the wavelength of radiation emitted by a celestial body as a consequence of the doppler effect.  

the great thing about your imagination is that it doesn't have to make sense! if i were you i would be stuck in space, no communication with earth travelling around and around, you can only guess how long its been since your communication broke down. you land on an undiscovered planet, you do a scientific investigation examining the elements and conditions. you come across alien lifeforms.  

best of luck!

the answer to the question is punishment. or more specifically, positive punishment.

positive punishment occurs when a behavior is given a negative consequence for the individual doing the behavior.

sara no longer wants to ask questions (the behavior) because she is ridiculed by mr. smith (the punishment).

reinforcement is inaccurate because reinforcement always gives positive consequences for the individual doing the behavior, be it by introducing a pleasant consequence or removing an unpleasant one.