Problema Solution
A merchant has coffee worth $60 a pound that she wishes to mix with 70 pounds of coffee worth $90 a pound to get a mixture that is worth $70 a pound. How many pounds of $60 coffee should be used?
Answer provided by our tutors
60x + 90*70 = 70*(x+70)
60x + 90*70 = 70x + 70*70
-10x = -20*70
x = 140 (amt. of $60 coffee needed)