After one week there should be 42 x 1.173 dung beetles.
After two weeks there should be 42 x 1.173 x 1.173 dung beetles.
After six weeks there should be 42 x 1.736 dung beetles.
The reason that you use 1.173 is: if there is no change, you would multiply by 1.000; you now need to add another 17.3% (which is 0.173); adding 1.000 and 0.173, you get 1.173.
The 1 means that you get to keep the original number; the 0.173 means that more will be added to the original number.
