Question

Pieces of metamorphic rock and pieces of sedimentary rock stick together to form a new rock. What type of rock do they form?

Answer 1

Most likely, this would be a conglomerate.

Explanation:

Conglomerates are a collection of older rocks that get cemented together and lithified (turned to stone). These older rocks can be brought down by erosion and then deposited in a new sedimentary environment in which they become lithified. So, you can end up with a rock (conglomerate) made of sedimentary rocks, metamorphic rocks and/or igneous rocks.

See pic.