Question $3.$

A beam is loaded as shown in Fig. $3$ a$).$ The beam is fabricated by welding two

channel sections together. Thils manufactured section is to be used in one of the

orientations shown in Fig. $3$ b$)$ and Fig. $3$ c$).$

For each orientation of the cross$-$section, calculate the maximum shear flow that will

occur in a weld. State clearly any assumptions that you make.

For this question I have found Ib and Ic already as $598*(10^3)$ and $2\mathrm{.}11*(10^6)-$ dont need this shown, I just need to know how to find Q$.$ The answer I have says for Qc$=46*8*44+2*40*8*20$ IDK how they got these values. They also said shear flow in b is $0$ which I also dont understand.