LL $($roof$)$: $20$ psf

DL $($roof$)$: $21$ psf

WD $($beam$)$: $50l\frac{b}{f}t$

Slope of roof $\frac{4}{12}$

Assuming beam material is $24F-1\mathrm{.}8GLB$

Using ASD method

$Cd=1\mathrm{.}15$

$Cm=1\mathrm{.}0$

$Ct=1\mathrm{.}0$

using the information provided design a gulam beam using ASD, thank you