X = (23+39)/ 2 = 62/2 = 31
answer
x = 31
Step-by-step explanation:
Given
One plain pizza and two sodas cost $15.95
Similarly, 3 plain pizzas and 5 sodas cost $45.90
Suppose the cost of single pizza and soda be
and 
In linear equation format, it can be written as

Therefore, the above two equations represents the given situation.
so, start floor = x
x + 7 - 9 - 4 + 8 - 2 = 14
x = 14
the elevator started on the 14th floor.
to verify: 14 + 7 = 21 - 9 = 12 - 4 = 8 + 8 = 16 - 2 = 14
Answer:
You would end up at (9,6)
The way you wrote the problem makes the answer 330,600. I think your decimals were meant to be commas. If I am wrong, please forgive me.