Question 986192
Hi there,
Using the formula
a + (n - 1) d
a is the first number of the sequence
d is the difference between nos of TVs

number of TVs = 11 + (n - 1)3
2000 = 11 + 3n - 3 
2000 = 8 + 3n
1992 = 3n
n = 664
On his 664 week Henk will sell his 2000th TV.
Hope this helps :-)