1. Mike has coffee worth $4 per pound that he wishes to mix with 20 pounds of
coffee worth $7 per pound to get a mixture that can be sold for $5 per pound,
How many pounds of the cheaper coffee should he use?

40 pounds

Step-by-step explanation:

1. Set up your equation, 4x+140=5x+100

2. Solve for x, x=40

26

step-by-step explanation:

solution:

→c= a b , that is product of a and b is possible only when when a is m × n matrix and b is n × p matrix.

that is, number of columns of a= number of rows of b.

so, size of matrix , c= a b is , if a = (m × n)matrix

b= (n × p)matrix

then a b = [ (m × n)matrix] ×[   (n × p)matrix ]

→→c= a b= [m × p ] matrix

→→size of product a b will be equal to = number of rows of a × number of columns of b