3rd grade
posted by nikki on .
mr.mancho my great dane ate 125 hot dogs over a five day period. each day he ate seven more hot dogs than on the previous day. how many hot dogs did he eat on the first day.....

Read DrWLS's explanation carefully.
http://www.jiskha.com/display.cgi?id=1287095215 
You need to use the strategy of working backwards
day 5= 125 hot dogs
day 4= 1257=???
day 3= ???7 etc.
day 2=
day 1=