Could somebody please help me ?

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 is working backward similar to solving an equation?

If y varies directly as x2 and y=6 when x=6, find the constant of variation.