Divide 24 by 6 in order to see how many six second intervals there are. 24/6=4. Multiply 4x5 to show many stories the elevator travels. The answer will be 20 stories.
The correct answer is option 2.
3 = 0
x - a = 0
x = a
x + b = 0
x = -b
We do not multiply any of these values by 3 because in a way, 3 is acting as another "zero" of the equation. Though, as shown above, it does not equal 0, it still does not apply to any of the other equations solved above.
Hope this helps!! :)