The answer is 50/50. The either child is a boy or a girl. 50/50 chance
Just plug in 3 for n and then 5 for n to see if an turns out to be 10 and 26.
n=3:
A) an = 8*3+10 = 34
B) an = 8*3 - 14 = 10 OK
C) an = 16*3+10 = 58
D) an = 16*3 - 38 = 10 OK
n=5:
B) an = 8*5-14 = 26 OK
D) an = 16*5 - 38 = 42
So the answer is B
Answer:

Step-by-step explanation:
Using the addition formulae for cosine
cos(x ± y) = cosxcosy ∓ sinxsiny
---------------------------------------------------------------
cos(120 + x) = cos120cosx - sin120sinx
= - cos60cosx - sin60sinx
= -
cosx -
sinx
squaring to obtain cos² (120 + x)
=
cos²x +
sinxcosx +
sin²x
--------------------------------------------------------------------
cos(120 - x) = cos120cosx + sin120sinx
= -cos60cosx + sin60sinx
= -
cosx +
sinx
squaring to obtain cos²(120 - x)
=
cos²x -
sinxcosx +
sin²x
--------------------------------------------------------------------------
Putting it all together
cos²x +
cos²x +
sinxcosx +
sin²x +
cos²x -
sinxcosx +
sin²x
= cos²x +
cos²x +
sin²x
=
cos²x +
sin²x
=
(cos²x + sin²x) = 
Answer:
what is this and give more info next time too
Step-by-step explanation: