In Aqueous Solution, Hypobromite Ion, BrO^-, Reacts to Produce Bromate

In aqueous solution, hypobromite ion, BrO^-, reacts to produce bromate ion, BrO₃^-, and bromide ion, Br^-, according to the following chemical equation: 3BrO^-(aq) → BrO₃^-(aq) + 2BR^-(aq)
A plot of 1/[BrO^-] vs. time is linear and the slope is equal to 0.056 L mol^-1 s^-1. If the initial concentration of BrO^- is 0.80 mol L^-1, how long will it take one-half of the BrO^- ion to react?

A) 4.5 × 10^-2 s
B) 7.1 s
C) 12 s
D) 22 s