Question

How much salt was to be added to 60 litres of a 20% solution of salt to increase it to a 40% solution of salt ?

Answer 1

In 60 litre, the amount of salt is 20% of 60=$\frac{20}{100}\times 60$
$=12$ ltr.
Let the amount of salt to be added be x to increase the solution of 40% solution salt.
So, the amount of salt in $60+x)$ ltr is (x+12) ltr to increase 40% solution salt.
$\Rightarrow x+12=\frac{40}{100}\times (60+x)$

$\Rightarrow 100x+1200=2400+40x$

$\Rightarrow 60x=1200$

$\therefore x=20$ ltr.