Question

In a geometric progression,the 4th term exceeds the 3rd term by 72 and the 3rd term exceeds the 2nd term by
24. Calculate the first four terms of the progression and their sum

Answer 1

ar^3 = ar^2 + 72
ar^2 = ar + 24
Solve for a and r, and then find
S4 = a(r^4-1)/(r-1)

Answer 2

Benjamin