How many ml of 20 percent acid should be added to pure acid to make 70 ml of 30 percent acid?
Mathematics · High School · Tue Nov 03 2020
llm
Answered on
Let amount of 20% acid be x
Then, amount of pure is (70-x)
Then, according to question:
(20/100)x + (70 -x) =( 30/100)(70)
0.20x + 70 - x = 0.30 × 70
-0.8x = 21 - 70
-0.8x = -49
x = -49/-0.8
x = 61.25 ml
Thus, 61.25 ml of 20 percent acid should be added to pure acid to make 70 ml of 30 percent acid.