A Monel Shell $\left(E_{m}=170 \mathrm{GPa}, d_{3}=12 \mathrm{~mm}, d_{2}=8 \mathrm{~mm}\right)$ Encloses a Brass Core

A monel shell $\left(E_{m}=170 \mathrm{GPa}, d_{3}=12 \mathrm{~mm}, d_{2}=8 \mathrm{~mm}\right)$ encloses a brass core $\left(E_{b}=96 \mathrm{GPa}, d_{1}=6 \mathrm{~mm}\right)$ . Initially, both shell and core are
A length of 100 mm. A load P is applied to both shell and core through
A cap plate. The load P required to compress both shell and core by
0)10 mm is approximately: (A) $10.2 \mathrm{kN}$
(B) $13.4 \mathrm{kN}$
(C) $18.5 \mathrm{kN}$
(D) $21.0 \mathrm{kN}$