Agirl wants to count the steps of a moving escalator which is going up. if she is going up on it, she counts 60 steps. if she is walking down, taking the same time per step, then she counts 90 steps. how many steps would she have to take in either direction, if the escalator were standing still?

Let

x--------> the speed of the girl in step

y--------> the speed of the escalator in step

d------> the distance between ground and floor.

we know that

when the girl is going up on escalator

----> equation

when the girl is going down on escalator

-------> equation

Adds equation and equation

--------> equation

Time to climb (in step) with y=0 (escalator standing still)

-----> equation

Substitute equation in equation

therefore

the answer is

hi there!

step-by-step explanation:

a roof pitch is basically for every inch rise there is 12 inches run.

the height of the roof is also known as the rafter.

formula: rafter^2 = rise^2 + run^2

rafter^2 = 5^2 + 12^2

rafter^2 = 25 + 144

rafter ^2 = 169"^2

the height of the roof from the lowest point to the highest point is 169"^2.

hope this : )