Please, someone, help me ASAP

Two lines parallel to a third line are parallel to each other. always sometimes or never

Two blends of tea are mixed to make a blend that will be sold at the fair. black tea sells for $2.20 per pound and orange pekoe tea sells for $3.00 per pound. how much of each should be used to obtain a 4lb blend selling for $2.50 per pound?

What are “like terms”? why can we only add like terms?