There are 3+1=<<3+1=4>>4 people in the house
So they drink 4*2=<<4*2=8>>8 cups of coffee a day
That means they use 8*.5=<<8*.5=4>>4 ounces of coffee a day
So they use 4*7=<<4*7=28>>28 ounces of coffee a week
So he spends 28*1.25=$<<28*1.25=35>>35
#### 35