Answer:
Take a look at explanation below;
Step-by-step explanation:
See attachment( s ) below;
The question is asking how many combinations of two people can be made from a group of ten people.
Using the formula C(10,2) = 10!/(2! x (10 - 2)! = 10!/(2! x 8!) = 45 handshakes.
A simple way to prove this is each person shakes the hand of 9 other people
10 x 9 = 90 but this counts every handshake from the view of both people involved.
The actual number of handshakes is therefore 90 / 2 = 45
For light: Inverse Square Law
<span>
The signal is weaken by the inverse square of the
difference of distances this means that one over the square of the
difference. </span>
<span>
</span>
Therefore, 70000LY / 141 LY =496.45 and that
squared =246462.602 times less signal, or 1/246462.602.
2 For a circular telescope like the
Arecibo radio telescope that equals Pi times the radius squared. Sensitivity
of the telescope depends on its area.<span>
The new telescope needs 246462.60 times that area to have
enough sensitivity </span>
<span>
<span>(150 x 150 x Pi) = 70 685 sq m area for the Arecibo telescope
and that times 246462.60
= 1.74212 x 10^10</span></span>
<span><span>
</span></span>
What is the diameter of a circle with that area?
<span>
<span>1. Divide the area by Pi = 5.548156 x 10^9
2. Take the square root of the result to find the radius = 74485.94293</span></span>
3. Multiply by 2 to find the diameter =
<span>148971.886</span>
