Question : One type of liquid contains 20% water, and the second type contains 35% water. A glass is filled with 10 parts of the first liquid and 4 parts of the second liquid. What is the percentage of water in the new mixture in the glass?

Question : If water is frozen to become ice, its volume is increased by 10%, then if the ice is melted to water again, its volume will be decreased by:

Question : The ratio of the volume of the two cones is 2 : 3, and the ratio of the radii of their bases is 1 : 2. The ratio of their heights is:

Question : A mixture of 70 litres of wine and water contains 10% of water. How much water must be added to make the water $12 \frac{1}{2}\%$ of the resulting mixture?

Question : In an experiment, it was observed that metal A is 19 times heavier than water and metal B is 9 times heavier than water. In what ratio are metals A and B mixed so that the mixture thus obtained is 15 times heavier than water?