150 ml
Let x be the volume of 20% solution to add. The amount of "stuff" dissolved in the 20% solution plus the amount in the 40% will equal the amount of "stuff" dissolved in the 25% solution.
(0.20)(X) + (0.40)(50 ml) = (0.25)(X+50ml)
0.2X + 20 = 0.25X + 12.5
20 - 12.5 = 0.25X - 0.20X
7.5 = 0.05X
X = 7.5/0.05 = 150 ml
2 gallons.
50 gallons @ 3% must be added.
0.25 gallons of water (or 1 quart)
4.2 quarts
98 mL
600ml.
10 liters.
2 gallons.
4 litres
Dissolve 15 g salt in 100 mL water.
2%
40.8 grams
50 gallons @ 3% must be added.
0.25 gallons of water (or 1 quart)
0.6 of a pint.
4.2 quarts
98 mL