We are interested in selecting 2 people from the 7-person task force.
n = 7
r = 2
nPr = n! / (n-r)!
7!
------
(7-2)!
=
7!
----
5!
7×6×5×4×3×2×1
------------------------
5×4×3×2×1
= 7×6
= 42
I think B
J U S T I F I C A T I O N
The X and Y angles created by lines intersection in the pictures are 18° and 54°.
Based on the picture, angle ∠MON is a right angle hence it has an 90° angle. We then know that the ∠MOA is 72°. Because angle ∠MOA lies within the angle ∠MON, hence we can write the following formula:
∠MON = ∠MOA +∠AON = 90°
∠MON = 72° + ∠AON = 90°
∠AON = 18° ... (i)
If we focus on the line CD being intersected by the line AB, hence we can conclude that the angles form by this intersection will follow these rules:
∠AOD = ∠BOC
∠AOC = ∠BOD
∠AOD + AOC = 180°
∠BOC + ∠BOD = 180°
Based on the picture, we know that:
∠BOC = x
∠AOC = ∠MOA + ∠MOC
∠AOC = 72° + y ...(ii)
∠AOD = ∠AON + ∠NOD
∠AOD = 18° +2x
∠BOC = 3x ... (iii)
Because we already know that ∠BOC = AOD, hence we could rewrite the formula into:
∠BOC = ∠AOD
3x = 18° + 2x
x = 18° ... (iv)
To find the value of y, we need to focus on angle ∠AOC. Based on the previous calculations and formulas, we know that:
∠AOC + ∠BOC = 180° ... (v)
Input equations (ii) and (iv) into (v)
∠AOC + ∠BOC = 180°
(72° + y) + 3x = 180°
72° + y + 3(18°) = 180°
126° + y = 180°
y = 54° ... (vi)
Learn more about the angles by lines intersection here: brainly.com/question/2077876?referrer=searchResults
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