eating olives

thanks to professor smudge (@ProfSmudge) 21/08/2015 for featuring and providing this context for a % question by John Mason (that he used at RME 17.2)

he used the third question on the classroom resource ('percentages of green olives') as an example of an unexpected answer: you need to eat a lot of olives to reduce the percentage by a small amount

the problems can be solved in a variety of ways

a ppt is here

 a mixture of olives

 a simpler view

Fawn Nguyen presents her usual assured and interesting 'rectangles/boxes' approach to one of these tasks here