How many kg of pure salt must be added to 8 kg of a 30% solution to obtain a 35% solution?

$1 \frac{1}{3}$kg of pure salt has to be added.
In 30% Solution 8 kg salt exists. So to make 35%solution total salt required is $\frac{8}{30} \cdot 35$ = $9 \frac{1}{3}$kg of salt. So $1 \frac{1}{3}$kg of pure salt has to be added.[Answer]