This question involves direct proportion which has the formula (y=kx) where y and x are the values which are proportional and k is the constant of proportionality.
The constant of proportionality is basically the value that stays the same even if the x and y values change.
In this case, the constant of proportionality would be 3/7.
Answer:
x= 4
Step-by-step explanation:
The answer is $2.50 because you do 145-132.50=12.5
Then you divide by 5 because that’s the difference between students then the final answer is 2.50
Your equation should be 5 - r + 2 = 3.