First find how much the electrician earns per day: $100/day * 2 = $<<100*2=200>>200/day
Then find how much the plumber earns per day: $100/day * 250% = $<<100*250*.01=250>>250/day
Then find how much both workers pay together: $100/day/worker * 2 workers = $<<100*2=200>>200/day
Then add the cost of each worker to find the total labor cost per day: $200/day + $250/day + $200/day = $<<200+250+200=650>>650/day
#### 650