A geometric progression has first term 2 and common ratio 23.
a. (i) Write the expression for the sum of its first n terms, Sn.
b. (ii) Set up an inequality to determine the least value of n for which Sn exceeds 1500.
c. (iii) Solve the inequality and state the least integer value of n that satisfies the given condition.
d. (iv) Verify your answer by calculating Sn for the value of n obtained.