I think what the question is saying is u get the bonus amount on the specified % for that bracket as (1000-0,3000-1000 etc)............. and the total will be--

0.5% of1000 + 1% of 2000+ 1.5 %of 3000 +2% of 4000

which equals = 150

hope this helps

Ya,

As with the question ...
First 1000$ ----> .5 percent of it is --->5 $

Second range is 1000-3000 ( as the bonus for 1st 1000 is already paid he wont be getting the bonus again)--- 2000-->1% of it is 20$

same logic applies here as well.. range for 3000-6000 he gets bonus pn;y for this range not the ones which is already added... so now 1.5 % of 3000 is 45 $

and so forth.... 6000-10000 --> 2% of 4000 which is 80$

so now annually he will get
5+20+45+80=150$

Hope it helps

Vishu