Answer: 
Step-by-step explanation:









This problem is a combination of the Poisson distribution and binomial distribution.
First, we need to find the probability of a single student sending less than 6 messages in a day, i.e.
P(X<6)=P(X=0)+P(X=1)+P(X=2)+P(X=3)+P(X=4)+P(X=5)
=0.006738+0.033690+0.084224+0.140374+0.175467+0.175467
= 0.615961
For ALL 20 students to send less than 6 messages, the probability is
P=C(20,20)*0.615961^20*(1-0.615961)^0
=6.18101*10^(-5) or approximately
=0.00006181
Answer: 
Step-by-step explanation:
Given
The temperature on the ground is 
temperature drop observed is 
The height of the plane is 
The total increase in height per
is
units
Temperature drop is

The temperature at that altitude is

Answer:
98°
142°
83°
97°
Step-by-step explanation:
m(arc)JL = 2 × 49° = 98°
m(arc)MJ = 360° - 120° - 98° = 142°
m<KJM = (120° + 46°)/2 = 83°
m<KLM = (360° - 120° - 46°)/2 = 97°