In a science experiment, the temperature of a substance is changed from 42 degrees to -54 degrees at an average rate of -12 degrees per hour. Over how many hours does the change take place?

There are a couple of ways to do this. The easiest is to take the number of degrees between 42 and - 54 and divide by 12.

Method

the number of degrees is abs(42) + abs(-54) = 42 + 54 = 96

Now divide by 12

Hours = 96 / 12 = 8 hours.

if you are saying purchasing 3 social media ads and one newspaper ad counts as one purchase then there are:

6 purchases

if you are asking how many of each then:

18 social media ads

6 newspaper ads

proportions are fractions that equal to each other. so if two fractions are the same, they are proportional.

let's check the answers to see if they are proportional.

question a is not proportional because you can't turn 1.5/3 to 3/9. if you try to multiply 1.5/3 by 2 or 3, you wont get 3/9. it's impossible to make the fractions the same.

question b is not proportional because you can't turn 22/33 to 4/6. 33 can't go into 6.

question c is proportional because when you multiply 2 and 3 by 71, you would get 142/213, and those fractions equal to each other

question d is proportional because when you divide 14 and 7 by 2, you would end up with 7/3.5, and those fractions equal to each other.