Answer: so the answer would be 0, to y
Step-by-step explanation: because that's what it's asking for
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

Answer:
282.7
Step-by-step explanation:
surface area of cylinder = 2πR² + 2πRh
R = 3 cm
h = 12 cm
surface area of cylinder = 2π*3² + 2π*3*12 = 90π ≈ 90*3.14 ≈ 282.7 (cm²)