The magnification is given as
m=hih0
As it is given that the height of the image is twice that of the object
m=2
We know that
hih0=−uiv0=2
By using the formula
1f=1u0+1vi
115=1u0−12u0
Hence for virtual image the distance of the object is 7.5cm and the distance of the image should be −15cm
For real image
By using the formula
m=−(−uiv0)
Hence the distance of the object is 7.5cm and the distance of the image should be −15cm