acid to be used , then the amount

of 30% acid is \(200-x\).

The amount of acid from the 80% solution is \(0.8x\), and the

amount of acid from the 30% solution is \(0.3(200-x)=60-0.3x\).

Setting these two amounts equal gives:

$$0.8x=0.3x+60$$

$$0.8x-0.3x=60$$

$$0.5x=60$$

$$x=120$$

Therefore, the chemist should use 120 liters of 80% acid and \(200-120 = 80\) liters of 30% acid.