Initially, a mixing vessel contains 300 kg of orange juice containing 40% solids. Orange concentrate and water are continuously fed into the vessel as illustrated in Figure 2.1. If it’s desired that the orange concentrate be diluted, how long should stirring occur to reduce the solids to 35%. [25] Fig 2.1: Mixing vessel

  forever (no solution)

Explanation:

If the figure you're working with is the one shown below, no amount of mixing will reduce the solid content to 35%.

The vessel contains 40% solids.

The incoming feed is ...

  (100 kg/h)×(60% solids) = 60 kg solids/h

out of a total influx of material of ...

  (100 kg/h +70 kg/h) = 170 kg/h

That means the solids content of the inflow is ...

  (60 kg)/(170 kg) = 0.352941 ≈ 35.3%

The solids content cannot ever be less than 35.3%. The problem has no solution.

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answer:

put more,