red and yellow spheres

picking twice, with replacement

a ppt is here

exploring whether or not you are more or less likely to obtain two spheres of the same colour (RR or YY) than two speres of different colours (RY or YR)

 or use a tree diagram

options with a total of 9 spheres still

various totals

you can just consider half of the diagram

is the fawn area larger or smaller than the red plus the yellow?

fold once

fold twice

approached algebraically

an alternative algebraic justification

utilising pythagoras to justify the result