Answer:
81.85%
Step-by-step explanation:
Given :
The average summer temperature in Anchorage is 69°F.
The daily temperature is normally distributed with a standard deviation of 7°F .
To Find:What percentage of the time would the temperature be between 55°F and 76°F?
Solution:
Mean = 
Standard deviation = 
Formula : 
Now At x = 55


At x = 76


Now to find P(55<z<76)
P(2<z<-1)=P(z<2)-P(z>-1)
Using z table :
P(2<z<-1)=P(z<2)-P(z>-1)=0.9772-0.1587=0.8185
Now percentage of the time would the temperature be between 55°F and 76°F = 
Hence If the daily temperature is normally distributed with a standard deviation of 7°F, 81.85% of the time would the temperature be between 55°F and 76°F.
6x/6y=6z
X/?Y=1/2Z
36=6
1hole take 1 man x 6 days
1/2 hole needs 1 man with 3 days
Frequency=(speed of sound)/(wavelength)
that means
wavelength =(speed of sound )/(frequency)
speed of sound=344 m/s
4.
frequency=587. 33 Hz
thus
wavelength=344/587.33
=0.586 m
5.
frequency=493.88 nHz
thus
wavelength=344/493.88
=0.69653 m
6. Frequency= 698.46 Hz
wavelength= 344/698.46
wavelength=0.4925 m
9. Frequency =783.99 Hz
wavelength=344/783.99
wavelength=0.439 m