Constraints on Ω _b f _IGM using the two FRB/GRB systems. Solid lines are calculated with DM _tot, while dashed lines are calculated with the estimated DM _IGM. The red lines are for GRB 101011A, while green lines are for GRB 100704A. The black solid line regime corresponds to the constrained range of Ω _b f _IGM. The horizontal black dotted lines are the favored region of the Planck+ WMAP results (Ade et al. 2013) corrected for f _IGM = 0.83 derived from Fukugita et al. (1998). The intersection of this band with the four lines give estimates of the redshifts of the two FRB/GRB systems: z = (0.554, 0.687) for GRB 101011A and z = (0.130, 0.246) for GRB 100704A.