My answer would be 8.. I may not be correct, but I tried. So, I placed the numbers from least to greatest and split it 1’s and 2’s VS 3’s and 4’s. I just added 1 plus 2 plus 2 and a half plus 2 and a half and got 8. I also added (3+3+3)+3 and a half plus 3
Let's assume the number be x.
So, sum of a number and 10 can be written as x+10.
Now the given statement is "One half of the sum of a number and 10 ".
So, one half of x+10 can be written as 
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
Jayce sold 28 bc $210/84 bars = $2.50 per bar. $70/2.50 = 28 bars
