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
Angle A would be 10 degrees.
Complementary angles add to 90 degrees.
So 90-80=10
16m/s * 8s = 128m Multiply out the time to get the total displacement from the descent.
128m-71m = 57m Find the displacement from the descent to the ascent and then add that to 1364m to get your answer.
1421m
.15 repeating which is the 2nd one
I think the correct answer is :D