Answer: c. 
Step-by-step explanation:
As per given , we have
Total number of residents injured from roller-skating =1,800
Total number of deaths from roller-skating = 90
Formula for Mortality rate : 
Then, the proportional mortality ratio (%) due to roller-skating was
=
= 5%
Hence, the correct answer is c.
To simplify the given radical form, we must recall some properties of exponents as shown below.
1. 1/x⁻ⁿ = xⁿ
2. x¹/² = √x
Now, going back to 1/x⁻³/⁶, we have
1/x⁻³/⁶ = x³/⁶
x³/⁶ = x¹/²
x¹/² = √x
Using the properties provided, we have a simplified form of √x.
<span>Answer: √x</span>
Define rates at which the individuals paint.
Bill: x = 1/8 signs/h
Bob: y = (2 signs)/(8 h) = 1/4 signs/h
Barry: z = (4/3 signs)/(8 h) = 1/6 signs/h
The job is to paint 2 signs, working together.
In the first 3 hours, the amount painted is
(x+y+z signs/h)*(3 h) = (1/8 + 1/4 + 1/6)*3 = 13/8 signs
Remaining: 2 - 13/8 = 3/8 signs
Barry quits.
In the next 1/2 hour (30 minutes), the amount painted is
(x + y signs/h)*(0.5 h) = (1/8 + 1/4)*0.5 = 3/16 signs
Remaining: 3/8 - 3/16 = 3/16 signs
Now Bob quits.
The time for Bill to finish the job is
(3/16 signs)/(1/8 signs/h) = 3/2 h
Answer: Bill finishes the job in 1.5 hours (or 1 hour, 30 minutes)
Louise’s answer is not correct. She is missing the term 30x3. When squaring a binomial, it is best to write the product of the binomial times itself. Then you can use the distributive property to multiply each term in the first binomial by each term in the second binomial. Louise also could have used the formula for a perfect square trinomial, which is found by squaring a binomial.
