ElectricPavlov

1)   I do not know..... I have never paid anything but I have only answered uestions ( thousands) 

2)  you get a point or two for posting an answer ( give one to yourself !) ...other users can give you a 'thumbs up' point too...and moderator CPhil will often give you a point and a recognition as 'Best  Answer' 

3) 'Top users'  only shows the top users who have logged on recently..... after a while of no activity the user will not show up unitl login on again

4)  Nope ....not that I am aware of..... didn't use to be that way.....things have kind of gone downhill on this website since AI was introduced...but I think they did it to cut down on abuse. bullying and nuisance posts.

5) No idea.... the number of moderators has not changed since I became a memeber a LONG time ago

6) 'onlie user' shows users who are actually logged on at the time

7) All sorts of topics are asked, but it is best if you put non-math topic in the headline when posting

This site used to be a very active AND interactive community with literally hundreds of questions posted everyday.  Everone was free to post what they thought to be the answer and you were able to edit your answers if you made a mistake .   You could also 'talk ' to people via the posts....

 all of this no longer exists and there are VERY few posts of questions these days.....yours is the first I have seen in over a week.

Maybe I'll see ya around ! 

   ~ EP 

It is green for   40 out of  (40+5+35) seconds = 40 out of 80 seconds 

   the probability that  you see green  watching it for 75 seconds means

                            you will see green in that  75 seconds EVERYTIME  or  100 %   ....there is no 75 seconds where it is not going to have at least a portion of a green phase.

1,0     0,1     and   0,0    would produce a triangle with area = 1/2 

Well, 

2 ( 5+3) = 16     so   q   or  r  could be    5 or 3 

Break it into 4 pieces as shown:

 1^1 + 2^2 + 3^4 + 4^8    = 

  1   +   4   +  81  +  65536 =   65622          Units digit = 2 

He first circles '2'    then circles the powers of 2 :  cirlces 4   circles  8  

He then circles '3'   then circles the powers of 3 :  circles 9 

He then circles '4'    no powers of 4 are on the list so no circles   and :

He then circles 5    then 6  ,7  ,10 ,11, 12 , 13 , 14  and lastly   '15 '

Now, he starts crossing:

   He  crosses off 15    then 14 , 12, 10 , 8 , 6, 4, ,2

    He then crosses off 13    then crosses off 11 , 9 ,7,5,and lastly '3'   

Last circled = 15     last crossed = 3           3 X 15 = 45