You can
put this solution on YOUR website!The number of chips is in geometric sequence (or geometric progression) where each term is 2 times the previous one (common ratio=2).
The nth question is worth
chips.
If the contestant answers the first n questions correctly, the number of accumulated chips will be the sum, S:
=
+
+
+
+ ..... +
+
Textbooks have formulas to calculate such sums, but I'd rather open my mind than a textbook.
Multiplying times 2:
=
+
+
+ ..... +
+
+
and subtracting the expression for S from the expression for 2S:
=
-
=
and
so the contestant has to aim for n+1=8, and answer the first 7 questions correctly.
