Answer
Each spring stretches by $0.04m$
Work Step by Step
When the object is hung from the 100-coil spring, $$W=F_1=kx_1 (1)$$ where $x_1=0.16m$
From Conceptual Example 2, we learn that the 50-coil spring has double the value of spring constant as the 100-coil spring does. So the restoring force each 50-coil spring has is $F_2=2kx_2$
There are 2 springs, and the system is still in equilibrium, so $$W=2F_2=4kx_2 (2)$$
From (1) and (2), $$kx_1=4kx_2$$ $$x_2=\frac{x_1}{4}=0.04m$$
