To save time you can approximate the initial volume of water to ±1 ml and the initial mass of the solid to ±1 g. for example, if you are asked to add 23 ml of water, add between 22 ml and 24 ml. which metals in each of the following sets will have equal density?

1. 20.2 g gold placed in 21.6 ml of water and 12.0 g copper placed in 21.6 ml of water.
2. 20.2 g silver placed in 21.6 ml of water and 12.0 g silver placed in 21.6 ml of water.
3. 15.2 g copper placed in 21.6 ml of water and 50.0 g copper placed in 23.4 ml of water.
4. 15.4 g gold placed in 20.0 ml of water and 15.7 g silver placed in 20.0 ml of water.
5. 20.2 g silver placed in 21.6 ml of water and 20.2 g copper placed in 21.6 ml of water.
6. 11.2 g gold placed in 21.6 ml of water and 14.9 g gold placed in 23.4 ml of water.

The correct answers are option 2, 3 and 6.

Explanation:

Density is defined as mas of substance present in an unit volume of the substance.

Density of same substance with different masses and volume remains the same that is it is an intensive property.

2. 20.2 g silver placed in 21.6 mL of water and 12.0 g silver placed in 21.6 mL of water.

3. 15.2 g copper placed in 21.6 mL of water and 50.0 g copper placed in 23.4 mL of water.

6. 11.2 g gold placed in 21.6 mL of water and 14.9 g gold placed in 23.4 mL of water.

Since the metal kept in both the cases are same.And metal has fix value of density , so from the given options the the option with sets of same of  metals has equal densities.

they it depends on if one believes about radioactivity, they make a geiger counter beep but maybe it was going to beep anyway electronics do wierd things all the time or it was programmed to beep near certain metals.