What is the simplest form for the fractions 12/30,12/20 and 21/35

Aformual for 8 bottles of window cleaner calls for 6 cups of rubbing to customers alcohol 2 1/4 gallons of water and 1 1/2 cups of ammonia alcohol would the forula call if a factory made 1,280 bottles for stores to sell to customers

This race was first held in 1953 on august 16th. every decade the race finishes with a festival. how many years is this?

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?