Roman mixes 12 litres of 8% acid solution with a 20% acid solution, which results in a 16% acid solution. How do you find the number of litres of 20% acid solution in the new mixture?

1 Answer
Dec 31, 2016

Answer:

The volume of 20 % acid is 24 L.

Explanation:

We can use the "volume × concentration" formula to work out the answer.

#"Volume of 8 % acid + volume of 20 % acid = volume of 16 % acid"#

Let #x# be the volume of 20 % acid.

Then #(12 + x)color(white)(l) "L"# is the new volume of the 16 % acid.

We can write

#V_1c_1 + V_2c_2 = V_3c_3#

#12 color(red)(cancel(color(black)("L"))) × 8 color(red)(cancel(color(black)(%))) + x color(red)(cancel(color(black)("L"))) × 20 color(red)(cancel(color(black)(%))) = (12 +x) color(red)(cancel(color(black)("L"))) × 16 color(red)(cancel(color(black)(%)))#

#96 + 20x = 192 + 16x#

#4x = "192 - 96" = 96#

#x = 96/4 = 24#

∴ The volume of 20 % acid is 24 L.