Amplifier question

[methodsboy]

hey
Checkpoints 2009 Question 420
it asks to calculate the gain of the amplifier. the Vout axes is in (V) whereas the Vin axes is in (mV)
Gradient = 20V / (4 x 10^-3)V = 5000 (inverting)
The answer says that the Gain is 5 (inverting)
if i remember: Gain = Vout (V) / Vin (V)
can someone confirm this or am i doing something wrong?
thanks 

[TrueTears]

I remember confirming with my teacher, the answer is wrong, you are correct. (They forgot to change the units haha)