Question

To earn an A in an algebra course, a student must have a test average of at least 90. Mary has grades of 95, 82, 88 on her first three algebra tests. What minimum score does Mary need to make on her fourth test to earn an A in her algebra course?

Answer 1

Answer: Mary need to make at-least 95 on her fourth test to earn an A in her algebra course.

Step-by-step explanation:

Let x be the grades scored by Mary in the fourth algebra test.

Mary has grades of 95, 82, 88 on her first three algebra tests.

Then, the combined scores in four test will become = 95+82+88+x =  265+x

Average score = (Sum of all scores) ÷ (Number of tests)

$=\dfrac{265+x}{4}$

As per given ,

To earn an A in an algebra course, a student must have a test average of at least 90.

i.e. Average score ≥ 90

$\Rightarrow\ \dfrac{265+x}{4}\geq90\\\\\Rightarrow\ 265+x\geq 90\times4=360\\\\\Rightarrow\ x\geq360-265 =95\\\\\Rightarrow\ x\geq90$

Hence, Mary need to make at-least 95 on her fourth test to earn an A in her algebra course.