Answer:
A) 0.0107
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean 
and standard deviation 
, the z-score of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Mean of 440 seconds and a standard deviation of 40 seconds.
This means that 
Find the probability that a randomly selected boy in secondary school can run the mile in less than 348 seconds.
This is the p-value of Z when X = 348. So
has a p-value of 0.0107, and thus, the correct answer is given by option A.
Answer:
sin(72°)=x÷20ft.
sin(72°)×20ft.= 19ft 252 inches
the ladder reach 19ft 252 inches tall on the building.
Step-by-step explanation:
We need to look at factors of 2, which are only 2 and 1... How do we get them to add to -3? Well, they have to be negative.
-2 + -1 = -3
What about the multiplication? A negative × a negative = a positive, so
-2 × -1 = 2
So your answer is
-2 and -1
(a+b+c)/2. this is your answer. if it had the numbers i would solve it fully, but it only has variables.
Both expression have the same denominator: 9x²-1. Thus it must not be 0.
9x²-1=(3x-1)(3x+1)=0, resulting x=+-1/3.
Restrictions: x in R\{-1/3, 1/3}
Adding those expressions:
E=(-x-2)/(9x²-1 ) + (-5x+4)/(9x²-1)=
(-x-2-5x+4)/(9x²-1)=(-6x+2)/(9x²-1)=
(-2)(3x-1)/(9x²-1)=-2/(3x+1)
E=-2/(3x+1)
