Answer:

Step-by-step explanation:

Check:

OK.
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.
Answer:
<h2>√512 by √512 </h2>
Step-by-step explanation:
Length the length and breadth of the rectangle be x and y.
Area of the rectangle A = Length * breadth
Perimeter P = 2(Length + Breadth)
A = xy and P = 2(x+y)
If the area of the rectangle is 512m², then 512 = xy
x = 512/y
Substituting x = 512/y into the formula for calculating the perimeter;
P = 2(512/y + y)
P = 1024/y + 2y
To get the value of y, we will set dP/dy to zero and solve.
dP/dy = -1024y⁻² + 2
-1024y⁻² + 2 = 0
-1024y⁻² = -2
512y⁻² = 1
y⁻² = 1/512
1/y² = 1/512
y² = 512
y = √512 m
On testing for minimum, we must know that the perimeter is at the minimum when y = √512
From xy = 512
x(√512) = 512
x = 512/√512
On rationalizing, x = 512/√512 * √512 /√512
x = 512√512 /512
x = √512 m
Hence, the dimensions of a rectangle is √512 m by √512 m
Answer: a) Length of wire to replace old one=9ft
b) Length of wire=3.09ft
Leftover wire=0.91ft
Step-by-step explanation: from the right angle triangle, Tan&=20/15
&=53.13°
Length of wire,x=cos 31.13=x/15
15cos31.13
X=9
b) Tan&=10/6
Tan^-110/6
&=59.05
Length= 6cos59.04
X=3.09
4-3.09=.91= leftover wire
Answer : The speed of both planes is 61.25 mph and 18.75 mph respectively.
Explanation:
Let the speed of first plane be x mph
Let the speed of second plane be y mph
Since we have given that difference of speeds is 80 mph
i.e. x - y= 80 (
1)
Distance between two planes = 3400 miles
As they are flying towards each other i.e. they are in the opposite direction.
So, Relative speed will be the sum of their speeds i.e.
Relative speed = x + y
And we know speed = 
Speed= 
⇒ Speed = 42.5 mph
Hence, Relative speed becomes 42.5 mph
⇒ x+y=42.5 (
2)
Now, by using the elimination method of solving the system of equation, we have ,
x= 61.25 mph
and y = 18.75 mph