For this you will have to make a tree diagram
it will be so much easier although there is a way to do it
probability of getting heads is = 1/2 there for 10 tosses its (1/20)^10
F(x)=x^2+x+5
then
F(3) would be the function evaluated at x=3, or 17.
anytime you see F(3) it is just whatever formula you are looking at evaluated when the variable is equal to 3.
1 hour=60 minutes 12×5=60
9×5=45
About 45 messages per hr
200 is the answer i know this because 40%of 200 is 80