There is a missing data in the text of the problem: the current drawn is 0.5 A (found on internet)
Solution:
The power used by the toaster is the product between the voltage V and the current I:

The toaster is used for a time of 2 hours: t=2h, therefore the energy used is equal to
mercury??????? my only guess
Answer:
0.625 A
Explanation:
Vs = 7500 V, Is = 0.01 A
Vp = 120 V
Let the primary current be Ip.
As the transformer is ideal, so input power is equal to the output power
Vp x Ip = Vs x Is
120 x Ip = 7500 x 0.01
Ip = 0.625 A
That measure is known as "acceleration"
a = ΔV / t
Hope this helps!