Question

IN A SOLUTION OF COMMON SALT IN WATER, THE RATIO OF SALT TO WATER WAS 30:70 AS PER WEIGHT,IF WE EVAPORATE 100 GRAMS OF WATER FROM ONE KILOGRAM OF THIS SOLUTION, WHAT WILL BE THE RATIO OF THE SALT TO WATER BY WEIGHT?

Answer 1

salt:water = 30:70
so in ikg solution salt=300g and water =700g.
now 100g water is evaporated so net water =600g so the ratio would be 300:600=1:2.
now for 100g the ratio would be (100/3):(200/3) i.e. approximately 33.33:66.67

Answer 2

Answer:

Let x be volume of original solution.

=> Qty of water = 0.85x

If 30L water evaporates, remaining water is 0.85x - 30

This is now equal to 80% of remaining solution.

=> 0.85x - 30 = 0.80(x - 30)

0.05x = 30 - 24 = 6

x = 6/0.05 = 600/5 = 120L