Answer:
The compound interest formula is :

Now, we have to find p.
A = 2000
r = 2.8% or 0.028
n = 1
t = 3
Putting the values in formula we get;

=>

=>

=>

So, p = $1840.99 rounded to $1841.
Part A: John should invest $1841 now to have $2000 in 3 years.
------------------------------------------------------------------------------------------------
Part B:
Now p = 1841
r = 0.028
n = 1
t = 5

=>

=>

A = $2113.46
Hence, John will have $2113.46 in 5 years.