An ice cube containing a lead piece in it is floating in a glass of water. As ice melts the water level will:

We know that lead is a heavy metal its density is too greater than water. But along with ice its float due to balance of buoyancy force and gravitational force. On floating conditions, according to Archimedes principle, when ice and lead is floating on water then water displaced is equal to the mass of lead and floating ice. So, the water level has risen. But when ice melts and lead shrinks then its volume is less than the volume of water displaced during its floating due to density of lead is much higher than water and ice. So, its water level falls down.