Katrina is fostering a kitten and needs to purchase cat litter. Clean cats cost $10 for a 25-pound bag, and Forever Fresh costs $18 for a 40-pound bag. What is the cost per pound of the better deal?
The Clean cats brand costs $0.40 per pound because 10 / 25 = <<10/25=0.4>>0.4
The Forever Fresh brand costs $.45 per pound because 18 / 40 = <<18/40=.45>>.45
The Clean Cats brand is the better deal because .4 < .45. Answer: \boxed{$.4}.