For this case, the first thing we are going to do is assume that all the tests are worth the same.
Then, we define a variable:
x: score of Mona's last test
We write now the inequality that models the problem:
From here, we clear the value of x:
Answer:
the lowest grade that Mona can get for her last test so that her test average is 90 or more is:
x = 87
Then, we define a variable:
x: score of Mona's last test
We write now the inequality that models the problem:
From here, we clear the value of x:
Answer:
the lowest grade that Mona can get for her last test so that her test average is 90 or more is:
x = 87