The lowest grade he could earn is 120% of the grade at the end of the semester.
The following statement is given:
I have 90% after about 75% of the semester.
We are asked to find the lowest grade by the end of this semester.
A percentage is a number expressed as a fraction of 100.
- 50% = 50/100 = 1/2
- 25% = 25/100 = 1/4
- 20% = 20/100 = 1/5.
We can write this statement "I have a 90% grade after about 75% of the semester" as:
90% grade = 75% semester.............(1)
By the end of the semester means at 100% semester.
Multiplying equation (1) by 100/ 75 on both sides of the equation.
We get,
(100/75) x 90% grade = (100/75) x 75% semester
(100 x 90)/75 % grade = 100% semester
120% grade = 100%
Thus the lowest grade he could earn is 120% of the grade at the end of the semester.
Learn more about Percentages here:
https://brainly.com/question/24159063
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