I feel dumb, please help.

In which source of water would a wave travel the fastest? o ice o cold o room temperature o hot mark this and return save and exit next

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?

How do you solving the solution of each system using elimination?