Answer:
a) Amount to be invested today = $506,830.9
b) She will retire in 10.5 years time
Explanation:
The amount to be invested by Sara Wiggum today at 4%  to accumulate $2 million in 35 years is called the Present Value.
Present value (PV) is  the discounted value of a future amount at the opportunity cost rate of return .  The amount to be invested now at a particular rate of return to equal a future sum.
Present Value (PV)= (1+r)^(-n) × Future cash flow
For Sarah, the
PV = (1+0.04)× (-35) × 2,000,000
     =  0.2534 × 2,000,000
      = 506,830.9415
Amount to be invested today = $506,830.9
<em>How soon will She retire at rate of 14% per annum?</em>
The PV is still  506,830.9415, 
 FV is still 2,000,000, 
But rate now is - 14%, and 
n - ?.  
so we need to work out "n"
Work out "n" as folows:
(1+0.14)^(-n) = 2000000/506,830.9
(1+0.14)^(-n)   = 3.9406
n =  log 3.9406/log 1.14
n = 10.5 years 
She will retire in 10.5 years time