f(x) = 1 + 0.75(x-1)
May 1 = f(1) = 1 + 0.75(1-1) ⇒ f(1) = 1 + 0 ⇒ f(1) = 1
May 2 = f(2) = 1 + 0.75(2-1) ⇒ f(2) = 1 + 0.75(1) ⇒ f(2) = 1.75
May 3 = f(3) = 1 + 0.75(3-1) ⇒ f(3) = 1 + 0.75(3-1) ⇒ f(3) = 1 + 1.50 ⇒ f(3) = 2.50
Assuming May 19 = f(19) = 1 + 0.75(19-1) = 1 + 13.50 = 14.50
Total deposit for the month of May.
May 31 = f(31) = 1 + 0.75(31-1) = 1 + 22.50 = 23.50
May = 31/2 (1 + 23.50) = 15.50 (24.50) = 379.75