How many kg of pure salt must be added to 8 kg of a 30% solution to obtain a 35% soltution? Round to the nearest tenth.

Answer 1

Let x be the number of kg added. the amount of NaCl initially present is
30% x 8 = 2.40 kg .
For the stronger mixture,
x + 2.4 = 0.35 (8.0 + x)= 2.8 + 0.35 x
0.65 x = 0.4
Solve for x

Answer 2

well consider the original solution.
IT has .3*8kg of salt in it, and .7*8kg water.

Newsalt+oldsalt=.35(8kg +newsalt)

.65Newsalt=.35*8 - .3*8=.4kg
solve for Newsalt.