Final answer:
Walter will pay a total of $8511.11 for a $6000 loan with 6% interest compounded annually over six years.
Step-by-step explanation:
The total amount Walter will pay for a $6000 loan at 6% interest compounded annually for six years can be calculated using the compound interest formula:
A = P(1 + r/n)^(nt)
Where: 
 A is the amount of money accumulated after n years, including interest. 
 P is the principal amount ($6000). 
 r is the annual interest rate (decimal) (0.06 for 6%). 
 n is the number of times that interest is compounded per year (1 for annually). 
 t is the time the money is invested or borrowed for, in years (6 years).
 By substituting the given values into the formula, we get:
 A = $6000(1 + 0.06/1)^(1*6) = $6000(1.06)^6
 Calculating this gives us:
 A = $6000 * 1.418519 = $8511.11
 Thus, Walter will pay a total of $8511.11 at the end of six years.