A feed stream contains H2, CO as well as a trace of CH4. Pure CH3OH is produced by means of a reactor, separator as well as recycle with purge to remove the non-reactive CH4. Feed stream composition is 67.3 mol% H2, 32.5 mol% CO and 0.2 mol% CH4. Reuse CH4 concentration is held at 3.2 mol% CH4. Explain what is the ratio of the feed stream to purge stream flow rates?