Dino works 20 hours at a rate of $10 an hour, which means that work pays him 20*10=<<20*10=200>>200 dollars a month
Dino works 30 hours at a rate of $20 an hour, which means that work pays him 30*20=<<30*20=600>>600 dollars a month
Dino works 5 hours at a rate of $40 an hour, which means that work pays him 5*40=<<5*40=200>>200 dollars a month
Altogether, this means Dino makes 200+200+600= <<200+200+600=1000>>1000 dollars a month.
You subtract Dino's expenses of 500 from this amount, meaning he has 1000-500=<<1000-500=500>>500 dollars at the end of the month
#### 500