The answers on the right are in reverse order to the questions on the left.
I find it easier to see if I have a picture.
Answer:
Afternoon class has more students.
Step-by-step explanation:
Let m be the number of students in the morning class and n be the number of students in the afternoon class.
The average score for the students in the morning class was 80, then the sum of their scores is 
The average score for the students in the afternoon class was 86, then the sum of their scores is 
The sum of the scores of both classes is

and the average score is

The average (arithmetic mean) score for the two classes combined was 84, then

This means n is greater, so afternoon class has more students.
Answer:
The last investment (C) has the least interest of $600
The other two investments (A and B) have the <u>same</u> amount of interest of $1800.
Step-by-step explanation:
<u>Simple Interest Formula</u>
I = Prt
where:
- I = interest earned
- P = principal
- r = interest rate (in decimal form)
- t = time (in years)
<u>Investment A</u>
- P = $2000
- r = 10% = 0.1
- t = 9 years
Substitute the given values into the formula and solve for I:
⇒ I = 2000(0.1)(9)
⇒ I = $1800
<u>Investment B</u>
- P = $3000
- r = 3% = 0.03
- t = 20 years
Substitute the given values into the formula and solve for I:
⇒ I = 3000(0.03)(20)
⇒ I = $1800
<u>Investment C</u>
- P = $2000
- r = 10% = 0.1
- t = 3 years
Substitute the given values into the formula and solve for I:
⇒ I = 2000(0.1)(3)
⇒ I = $600
The last investment (C) has the least interest of $600.
The other two investments (A and B) have the <u>same</u> amount of interest of $1800.
(f + g)(x) = f (x) + g(x)
= [3x + 2] + [4 – 5x]
= 3x + 2 + 4 – 5x
= 3x – 5x + 2 + 4
= –2x + 6