Question

Aldos coffee shop makes a blend that is a mixture of two types of coffee. Type A coffee costs Aldo $5.80 per pound, and type of B coffee costs $4.65 per pound. This month, Aldo made 156 pounds of the blend, for a total cost of $826.60. How many pounds of type B coffee did he use?

Answer 1

Let A represent amount of Type A coffee pounds used. 
Let B represent amount of Type B coffee pounds used

A + B = 156 
B = 156 - A 
A = 156 - B

5.80A + 4.65B = 826.60 
580 (156 - B) + 4.65B - 826.60 = 0 
904.8 - 5.80B + 4.65B - 826.60 = 0
904.8 - 1.15B - 826.60 = 0 
78.2 - 1.15B = 0 
78.2/1.15 = 1.15B/1.15
68 = B
B = 68 pounds of Type B coffee

There's many more steps you can take to check and etc but am too lazy to put down sorry.