Please help, I think I know the answer am I correct? +90 + -77

I got= -13

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?

Acd that is originally priced at $15.85 red-tagged for the sale. what is the sale price of the cd

Bob the builder is making 480kg of cement mix. this is made by cement, sand and gravel in the ratio 1: 3: 4