Answer:
120 ml
Step-by-step explanation:
Let x ml of 5% acid should mix with 60 milliliters of 20% acid to obtain a 10% solution,
Thus, the quantity of resultant mixture = ( x + 60 ) ml,
Also,
Acid in x ml 5% acid + Acid in x ml 5% acid = acid in 10% resultant solution,
5% of x + 20% of 60 = 10% of ( x + 60)
[tex]\frac{5x}{100}+\frac{20\times 60}{100}=\frac{10\times (x+60)}{100}[/tex]
[tex]5x + 1200 = 10x + 600[/tex]
[tex]5x - 10x = 600 - 1200[/tex]
[tex]-5x = -600[/tex]
[tex]\implies x = \frac{-600}{-5}=120[/tex]
Hence, 120 ml of 5% acid should be mixed.
