Mary deposits R400 every three months into a bank account earning interest at 16% per year, compounded quarterly. The approximate time that it will take Mary to save R40000 is

The approximate time that it will take Mary to save R40000 is 29 years

Step-by-step explanation:

A= p(1+r/n)^nt

t = log(A/P) / n[log(1 + r/n)]

A = R40000

n = 4

P = R400

r = 16%

t = log(A/P) / n[log(1 + r/n)]

= log(40,000 / 400) / 4{log(1+0.16/4)}

= log(100) / 4{log(1+0.04)}

= 2 / 4{log(1.04)}

= 2 / 4(0.0170)

= 2 / 0.068

= 29.41

t = 29.41 years

Approximately 29 years

The approximate time that it will take Mary to save R40000 is 29 years

its a straight line parallel to the time axis