Answer:
x = 6
Step-by-step explanation:
8x + 2 + 70 + 60 = 180
8x + 132 = 180
8x = 48
x = 6
No, it is not a valid inference because her classmates do not make up a random sample of the students in the school.
We are given : $168 raised for washing 24 cars and $280 raised for washing 40 cars.
We know the rate formula.
Rate = Total amount ÷ Total numbers.
Let us find value of each rate for the given problem.
Rate 1: Total amount ÷ Total numbers = $168 ÷ 24 = $7.
Rate 2: Total amount ÷ Total numbers = $280 ÷ 40 = $7.
We can clearly see that Rate 1 is equal to Rate 2, that is $7.
So, we can say rates are equivalent.
The answer to the question is (2,-2)