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Leila's Coffee Shop makes a blend that is a mixture of two types of coffee. Type A coffee costs Leila $5.85 per pound, and type B coffee costs $4.40 per pound. This month, Leila made 147 pounds of the blend, for a total cost of $786.00 . How many pounds of type B coffee did she use?

Respuesta :

a + b = 147....a = 147 - b
5.85a + 4.40b = 786

5.85(147 - b) + 4.40b = 786
859.95 - 5.85b + 4.40b = 786
-5.85b + 4.40b = 786 - 859.95
- 1.45b = -73.95
b = -73.95 / -1.45
b = 51 <== she used 51 lbs of type B coffee