A manufacturer has 600 litres of a 12% solution of acid. How many litres of a 30% acid solution must be added to it so that acid content in the resulting mixture will be more than 15% but less than 18%?

A manufacturer has 600 liters of 12% solution of acid. How many litres of a 30% acid solution must be added to it so that the acid content in the resulting mixture will be more then 15% but less than 18%?

How may litres of water will have to be added to 1125 litres of the 45 % solution of acid so that the resulting mixture will contain more than 25 % but less than 30% acid content?

How many liters of a 25% saline solution must be added to 3 liters of a 10% saline solution to obtain a 15% saline solution?

How many times a fair coin must be tossed, so that the probabillity of getting at least one tail is more than 90 %

How much pure alcohol be added to 400 ml of a 15% solution to make its strength 32%?

90% acid solution (90% pure acid and 10% water) and 97% acid solution are mixed to obtain 21 litres of 95% acid solution. How many litres of each solution are mixed.

Solution of a monobasic acid has a pH=5. If one mL of it is diluted to 1 litre, what will be the pH of the resulting solution ?

How many times must a man toss a fair coin, so that the probability of having at least one head is more than 80%?

A solution of 8% boric acid is to be diluted by adding a 2% boric acid solution to it. The resulting mixture is to be more than 4% but less than 6% boric acid. If there are 640 litres of the 8% solution, how many litres of 2% solution will have to be added?

An exterminator needs to dilute a 25% solution of an insecticide with a 15% solution of the same insecticide. How many more liters of the 25% solution that the 15% solution are needed to make a total of 80 liters of a 22% solution of the insecticide?