An object \( AB \) is placed \( 15 \, \text{cm} \) on the left of a convex lens \( P \) of focal length \( 10 \, \text{cm} \). Another convex lens \( Q \) is now placed \( 15 \, \text{cm} \) right of lens \( P \). If the focal length of lens \( Q \) is \( 15 \, \text{cm} \), the final image is ____________ .