Kyle put "two" rectangles together to make this shape, so cut the shape into two. Then we know the bottom of one of the rectangles which is 16 is subtracted by 8 because half of 16 is 8 and 8 is one the measurements.
So the possible ways of throwing a sum of 10 is 4&6, 5&5, 6&4. All possible ways of throwing a pair of dice equal 36, so divide 3 by 36. Then, divide this number by 9 to get the possibility of it being at least 9 times, because the last throw doesn't affect it.
If there is 10% of $18 = 18 x 0.9 (1 - 0.1) = $16.20
Therefore the pie costs $16.20
He is saving 18 - 16.20 = $1.80