6(2 + 5t) = 6*2 + 6*5t = 12 + 30t
Answer is 12 +30t.
We know that
applying the Pythagoras theorem
LM²=LV²+VM²
LM is the radius of the circle
LV=5 in
VM=12/2----> 6 in
so
LM²=5²+6²-----> LM²=61------> LM=7.81 in------> LM=7.8 in
the answer is
7.8 in
21
E (225-25n)
n=1
So its D.