First, you need to get rid of all the blue slices, leaving 6 behind. Since they are all less than 9, you have a 6/10 chance of getting a white slices less than 9 :)
$210 because if it rose 30%, it's now 130% of what is used to be or (what it used to be) ×1.3 so do the reverse and divide the new cost by 1.3 so 273÷1.3 which is 210
