human
Madeline and her roommate, Keenan, share the cost of groceries. In total, they spend about $400 per month. In a four-week month, how many dollars does Keenan spend per week if Madeline pays 60% of the cost?
assistant
How much do they spend in a week? ** They spend $400/4=$<<400/4=100>>100 per week.
How much does Keenan pay? ** Keenan pays for 100-60=<<100-60=40>>40% of the groceries.
How much does Keenan spend? ** Thus, she spends $100*(40/100)=$<<100*40/100=40>>40 per week.
#### 40