When person is standing on a bathroom scale
then the reading of the scale is the measurement of normal force on the scale
so here we can see that normal force is 0.64 times the weight of the person
This shows that the normal force is less than the weight
It shows that elevator must have to accelerated downward direction
so here we will use the force equation
here we know that
also we know that
now we have
so acceleration of elevator will be 3.53 m/s^2 in downward direction