N=n(n−1)÷2
For example there are 12 people he
So
N=12(12–1)÷2=132÷2=66
That's for once but they handshaked after the meeting so
66∗2=132
Hope this helps!
~LENA~
Answer:
I think it's commensalism
Explanation:
The reaction of atomic N with neutrons in the upper atmosphere
Answer:
20ppm
Explanation:
parts per million are defined as the mass of solute in mg (In this case, mass of DDT) per kg of sample.
To solve this question we must find the mass of DDT in mg and the mass of sample in kg:
<em>Mass DDT:</em>
0.10g * (1000mg / 1g) = 100mg
<em>Mass sample:</em>
5000g * (1kg / 1000g) = 5kg
Parts per Million:
100mg / 5kg =
<h3>20ppm</h3>
