Question

For the series 16, 24, 36, 54... find s7

A)
32.17
B)
115.75
514.75
D)
3906.25

Answer 1

C.) 514.75

Explanation:

r = 24/16 = 1.5

r = 36/24 = 1.5

r = 54/36 = 1.5

16 + 24 + 36 + 54 + 81 + 121.5 + 182.25 = 514.75

or use:

Sn = a[ (1-r^n) / (1 - r) ]

S7 = 16[ (1 - 1.5^7) / (1 - 1.5) ]