Answer: He earned 0.831% interest in total.
Step-by-step explanation:
Given: Shawn earned $2.77 per day for three days as interest on his $1,000.00 investment.
Interest per day = $2.77
Interest in 3 days = 3 x ($2.77)
= $8.31
Invested amount= $1000
Required percentage of earnings = 

Hence, he earned 0.831% interest in total.
B because it =90 so it is Complementary
Where is the rest of the question?
X = 20
First, you move the 40 to the other side.
-2x=-40
Then, you divided -40 by -2.
x= -40/-2
x= 20
x is 20 because the negatives cancel out making it positive.
The answer should be x=100