Sue has 20 biscuits in a tin

In the diagram of circle o, what is the measure of zabc?

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25

How many heads would you expect if you flipped a coin twice? first, fill in the table below with the correct probabilities. hint: the sample space for flipping a coin twice is {hh, ht, th, tt}. a = b = c = f