SOLUTION: Martha entered the elevator and went down 7 floors, up 10 floors, up two floors, then down five floors. She was on the eleventh floor. What floor did she enter the elevator?

Question 585373: Martha entered the elevator and went down 7 floors, up 10 floors, up two floors, then down five floors. She was on the eleventh floor. What floor did she enter the elevator?
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
"went down 7 floors" ---> -7
"up 10 floors" ---> +10
"up two floors ---> +2
"down five floors" --> -5

Add up the figures to get: -7 + 10 + 2 + (-5) = 0

So her net change is 0 floors (ie after all that, she hasn't gone up or down). Therefore, if she ended on the 11th floor, this must mean she started on the 11th floor.
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