Find the unit rate
a) 180 miles in 3 hours (how many miles in 1 hour)
b) 256 miles per 8 gallons (how many miles per gallon)
c) $9.60 for 4 pounds (how much per pound)
d) $4.80 for 6 cans (how much per can)
e) 297 words in 5.5 minutes (how many word per minute)