John is a door-to-door salesman.  He visits 50 houses a day.  20% of them buy something from them.  Of those that buy something half buy a $50 set of knives and the other half buy a $150 set of knives.  How much does he sell a week when he works 5 days a week?
There are 50*.2=<<50*.2=10>>10 houses buying from him per day
Of those 10/2=<<10/2=5>>5 buy each type of knife set
So he gets 5*50=$<<5*50=250>>250 per day from the cheap set
He also gets 5*150=$<<5*150=750>>750 from the expensive set
So he makes a total of 250+750=$<<250+750=1000>>1000 per day
That means he makes 1000*5=$<<1000*5=5000>>5000
#### 5000