Answer:
a = ± 4
Step-by-step explanation:
Expressing the proportion in fractional form
=
( cross- multiply )
(a -1 )(a + 1) = 15 ← expand factors on left side
a² - 1 = 15 ( add 1 to both sides )
a² = 16 ( take the square root of both sides )
a = ± = ± 4
*a clearer picture containing the graph is shown in the attachment
Answer:
20% of the class earned a D
Step-by-step Explanation:
Step 1: Determine the total number of students represented on the graph:
9 students => D
5 students => C
14 students => B
17 students => A
Total number of students = 45
Step 2: Express each category of students who scored a particular grade as a fraction and as percentage.
9 students => D => => as percentage, we have
5 students => C => => as percentage, we have
14 students => B => => as percentage, we have
17 students => A => => as percentage, we have
Step 3: Check each statement to see if they are true or not based on the calculations above.
Statement 1: "⅕ of the students earned a C."
This is NOT TRUE From our calculation, ⅑ of the students earned a C.
Statement 2: "3% more students earned an A than a B." This is also NOT TRUE.
37.8% earned A, while 31.1% earned a B. Thus, about 6.7% more students earned an A than a B.
Statement 3: "20% of the class earned a D". This is TRUE.
Check calculation in step 2.
Statement 4: "¼ of the class earned a B". This is NOT TRUE.
¼ is 25% of the class. Those who earned a B account for 31.1% not 25% (¼ of the class).
The correct statement is: "20% of the class earned a D"
