Total load =50+100= 150kN
Taking moments about A
RB x 4 = 50 x 1 + 100 x 3
RB x 4 = 350
RB= 350/4 = 87.5kN
RA= Total load – RB
RA= 150 – 87.5 = 62.5kN
( or)
Taking moments about B
RA x 4 = 100×1 +50×3
RA x 4 = 250
RA= 250/4 = 62.5kN
RB = Total load – 62.5
RB= 150-62.5 = 87.5kN