Answer:
on the number line make an open circle at 80 (am open circle is this: ○) and connect that to an arrow that points back to 0 and the negative numbers. It doesn't matter how far back as long as you make it an arrow
7 people so first one shakes hand with the remaining people. that is 6
The 2nd person also shakes hand with 6 persons but we have already counted his handshake with first person. so we have to add 6-1 = 5 shakes for 2nd person
like wise 3rd person shakes hand with the remaining 6-2 = 4 people
4th person with 6-3=3 people
5th person with 6-4= 2 persons
6th person with 6-5=1 person
and 7th one with no one because already he has shaken his hand with everyone.
since these people shake their hands with others only once we just have to add the obtained values
6+5 +4+3+2+1= 21
totally 21 handshakes will be there in that room
The integer is positive 4.
B/c-
4 • 4 = 16
9/20 because if you count the red and blue out of the 20, theres 9. So you have a 9/20 chance it will hit red or blue.