Object distance (u) = -25 cm (negative because the object is in front of the mirror)
Using 1f\frac{1}{f}f1 = 1u\frac{1}{u}u1 + 1v\frac{1}{v}v1
1f\frac{1}{f}f1 = 1−25\frac{1}{-25}−251 + 15\frac{1}{5}51
f = 254\frac{25}{4}425 = 6.250cm.
