If the strength of the magnetic field at B is 3 units, the strength of the magnetic field at A is 12 units
Magnetic field strength is one of two ways that the intensity of a magnetic field can be expressed.
The strength of the field is inversely proportional to the square of the distance from the source. This means that If the distance between two points in magnetic filed is doubled the magnetic force between them will fall to a quarter of the initial value.
On the other hand, if the distance between two magnets is halved the magnetic force between them will increase to four times the initial value.
