A newspaper gets 10000 commisson in a particular year, after every he gets 2000 more than preceding year. How long does it take to get 442000
This is just an AP, with (in thousands)
a = 10
d = 2
Your question is ambiguous.
If you want n where his annual commission is 442K
10 + 2(n-1) >= 442
Since I doubt he'll live that many years, I expect you meant how long till his total commissions are 442K. If so, then
n/2 (20 + 2(n-1)) >= 442