Answer:
310.5 J
Explanation:
The total work done by Martha is equal to the increase in gravitational potential energy of the package, which is equal to

where
(mg) = 45 N is the weight of the package
is the increase in height of the package
The package is carried up 3 flights of stairs, each one with a height of 2.3 m, so the total increase in heigth is

And so, the work done by Martha is

During a single replacement, the Zn and H will switch places. That means the product formed will be ZnCl and H2.
A) 5 kg block of wood
B) 100 kg person
C) 412 kg motorcycle
D) 2540 kg elephant
Answer: D