Given:
Confidence level = 90%
mean = 71 beats per minute
standard deviation = 6 beats per minute
margin of error = z * δ / √n
where : δ - population of the standard deviation, n is the sample size ; z is the appropriate z value.
90% confidence level = 1.645 in z-value
margin of error = 1.645 * (6/√80) = 1.645 * (6/8.94) = 1.645 * 0.671 = 1.104
The margin of error is 1.10
She can use 68 + 20 = 88 to help by noticing that the 20 is ahead of 19 by 1. She can easily mentally turn the 20 into a 19 and realized that the 88 would become 87.
How many did he lose? Can you tell us how much he lost?
Answer:Amount of white paint used by Sarah =1.82 pints
Step-by-step explanation:
Amount of blue paint and white paint to paint her bedroom walls.=9.1 pints
Amount of blue paint used =4/5 x 9.1=7.28 pints
Amount of white paint used=Amount of blue paint and white paint to paint her bedroom walls -Amount of blue paint used
=9.1-7.28=1.82 pints
Answer:
400 m^2.
Step-by-step explanation:
The largest area is obtained where the enclosure is a square.
I think that's the right answer because a square is a special form of a rectangle.
So the square would be 20 * 20 = 400 m^2.
Proof:
Let the sides of the rectangle be x and y m long
The area A = xy.
Also the perimeter 2x + 2y = 80
x + y = 40
y = 40 - x.
So substituting for y in A = xy:-
A = x(40 - x)
A = 40x - x^2
For maximum value of A we find the derivative and equate it to 0:
derivative A' = 40 - 2x = 0
2x = 40
x = 20.
So y = 40 - x
= 40 - 20
=20
x and y are the same value so x = y.
Therefore for maximum area the rectangle is a square.
