How do I break this down to answer it?

Question

A chemist is preparing a saline solution​ (salt water) for an experiment. She has 281 ounces of a 50​% saline solution. How many ounces of a ​30% saline solution need to be added to her original solution in order for her to have a solution with 198.1 ounces of salt in the​ mixture?

Answer 1

281(.5) + x(.3) = 198.1

.3x = 198.1 - 140.5 = 57.6

x = 576/3 = 192 ounces of 30% saline solution

281(.5)+ 192(.3)

= 140.5 + 57.6

= 198.1 salt which is 198.1/(281+192) = 198.1/473 = about .418816 = about 41.88%

mix 30% and 50% yielded about 42%

50-42 = 8

42-30 =12

there should be about 12/8 = 3/2 = 1.5 times as much 50% as 30%

281/192 = about 1.5