There is a 6 dancer difference I mean that should be a pretty obvious answer.
Answer:
13 seconds.
Step-by-step explanation:
Given

Required
Determine a reasonable solution for t
To do this, we equate h to 0.
becomes

Divide through by -4.9

Reorder the expression

Split
or 
This gives:
or 
But time can't be negative, So:

Answer:
I'm going out on a branch and say B
X= 48 is the correct answer. You can always plug in 48 back into the original equation and make sure it works.
48-23+84+48+23=180