Keeping track of information with a table

One thousand kilograms per hour of a mixture of benzene (B) and toluene(T) that contains 50% benzene by mass are separated by distillation into two fractions. The mass flow rate of benzene in the top stream is 450 kg B/h, and that of toluene in the bottom stream is 475 kg T/h. The operation is at steady state. Write balances on benzene and toluene to calculate the unknown component flow rates in the output streams.

For benzene, then,

F_feed=F_overhead + F_bottoms

500 = 450 + F_{bottoms, benzene}

F_{bottoms, benzene}=500 - 450 = 50 kg/h

Streams\mass flow rate	Total	Benzene	Toluene
Feed	1000	500
Overhead		450
Bottoms		50	475

Also, we know that the total flowrate of any stream is the sum of all the components in that stream. So, for example,

F_{feed, total}=F_{feed, benzene} + F_{feed, toluene}

Where should we click next to use this equation?