This is one of those achievements that you will get as you go for the "get 40,000 in your food bank" achievement. You can try "rubberbanding" your controller and all that, but honestly, it doesn't really work except on certain levels, as noted below. Don't worry about it, just keep playing for the food bank achievement and it will probably pop up during that. Yay efficiency!
And no, having your game paused doesn't count towards it.
If you did plan well and got your 40,000 before this, one of the comments suggests that you should rubberband on level 10. Make sure you plug in your controller.