Julie started with 20 pieces if gum and gave away x pieces. Conrad started with 35 pieces of gum and gave away twice as many pieces as Julie did. How many pieces of gum did Julie give away if they had the same number of pieces of gum left?

reflection is the bouncing back of a propagating wave when it encounters a barrier; usually shows an image of the source of light wave

1) bounces back from an opaque material

2) bounces back from the boundary

3) seen in mirrors

refraction is the bending of a propagating wave having a shift of direction as it passes through different media; usually seen in lenses to magnify or lessen

1) passes through a prism

2) moves from one medium to another

3) seen in lenses