PART (A):
As the total amount increases double each month. It is a geometric sequence equation. Fill the table.
Geometric Sequence: y = a(r)ˣ⁻¹
Here given:
First term (a) = 40
Common Difference (d) = 2
Equation: y = 40(2)ˣ⁻¹
After 1 year: y = 40(2)¹²⁻¹ = $81920

PART (B):
As the amount increases by $50 each month. It is a arithmetic or linear sequence.
Linear Equation: y = mx + b
Here given:
slope (m) = 50
starting (b) = 30
Equation: y = 50x + 30
After 1 year: y = 50(12) + 30 = 630