Answer: 68
Step-by-step explanation:
As per given , we have
Population standard deviation : 
Critical value for 90% confidence interval =
Margin of error : E= 0.8 milligrams
The formula to find the sample size is given by :-

i.e. 

Hence, the limnologist must analyze 68 samples.
The point on the graph represents that 2 books cost $10.
Answer:
We get ∠A =40° and ∠B = 140° and ∠B = 140° is measure of larger angle
Step-by-step explanation:
we have ∠A = (2x − 30)° and ∠B = 4x, and we need to find measure of larger angle. And ∠A and ∠A are supplementary angles.
If the angles are supplementary there sum is equal to 180° i.e ∠A + ∠B = 180°
So, First we have to find the value of x. and then we can determine larger angle.
We know: ∠A + ∠B = 180
2x-30+4x=180
6x-30=180
6x=180+30
6x=210
x=210/6
x=35
So, value of x is x=35
Now finding ∠A and ∠B
∠A = (2x − 30)°
∠A = (2(35) − 30)°
∠A = (70 − 30)°
∠A =40°
and ∠B = 4x
∠B = 4(35)
∠B = 140°
So, we get ∠A =40° and ∠B = 140° and ∠B = 140° is measure of larger angle
Answer:
Final price: $14.99
Step-by-step explanation:
Discount= original price x discount % / 100
Discount= 19.99 x 25/ 100
Discount= 499.75/100
You save= $4.9975
Final Price= original price - discount
Final price= 19.99 - 4.9975
Final Price= $14.9925
Final Price= $14.99
Answer:
x=-20/18
Step-by-step explanation:
-1/2x=(5x+10)/8= -18x=20
therefore x=-20/18 =-1.111111