A chemical company makes two brands of antifreeze. The first brand is 55% pure antifreeze, and the second brand is 75% pure antifreeze. In order to obtain 60 gallons of a mixture that contains 60% pure antifreeze, how many gallons of each brand of antifreeze must be used

At the "no mutants allowed" country farm, every sheep has 4 legs, every chicken has two legs, and all animals have only 1 head. asked to count how many sheep and chicken are in the fields, a farm boy reports back that there are 140 feet and 50 heads. how many sheep and chicken are there? there are sheep and chicken at the farm.