In a gas chromatography experiment, a mixture of two compounds (A and B) was separated for analysis. A chart recorder that fed paper at a constant rate of 100 mm. per minute was used to record the chromatogram, and a mark was made on the chart at the time the sample was injected. The first peak on the chromatogram corresponds to compound A, and that peak was observed at a distance of 4.01 cm from the sample injection point, and it had a height of 3 cm and a width at half-height of 1.38 cm. The peak corresponding to B was observed at a distance of 7.19 cm from the injection point, and it had a height of 3.07 cm and a width at half-height of 1.79 cm. What was the retention time for compound B (in seconds)