Ted must have an average of 70 or more in his summer course to obtain a grade of C. His first three test grades were 75, 63,and 68. Write an inequality representing the score that Ted must get on the last test to get a C grade.
Let X be the grade on the next test. The average is
(75+63+68+x)/4
That must equal or exceed 70.
Write that in mathematical form and convert ito an inequality for x.
79
To find the average grade, we need to add up all the scores and divide by the number of scores. In this case, there are 4 scores including the one we are looking for.
The average formula is:
Average = (sum of all scores) / (number of scores)
So, the average formula for Ted's grades becomes:
Average = (75 + 63 + 68 + x) / 4
Since Ted needs an average of 70 or more to obtain a grade of C, we can write the inequality as:
(75 + 63 + 68 + x) / 4 ≥ 70
To solve for x, we can multiply both sides of the inequality by 4 to get rid of the denominator:
75 + 63 + 68 + x ≥ 70 * 4
Simplifying the expression:
206 + x ≥ 280
Finally, we subtract 206 from both sides of the inequality to isolate x:
x ≥ 280 - 206
After performing the subtraction:
x ≥ 74
So, the inequality representing the score that Ted must get on the last test to get a C grade is x ≥ 74.