Pls answer this question...

Dear Student,

f = -15 cm

v = -10 cm 
Applying lens formula 

1/f = 1/v - 1/u

-1/15 = -1/10 - 1/u

-1/15 + 1/10 = -1/u

(-2+3)/30 = -1/u

1/30 = -1/u

u = -30 cm 

Hence, object should be placed 30 cm from the lens

m = v/u

m = (-10) / (-30)

m = 1/3

Hence, magnification produced by the lens is 1/3.

Regards