Question

Brand A coffee sells for $7/pound, while Brand B sells for $5.40/pound. How much of each brand of coffee is needed to make 5 pounds that will cost

$6.75/pound?

A. 0.8 pounds Brand A, 4.2 pounds Brand B
B. 2.7 pounds Brand A. 2.3 pounds Brand B
C. 4.2 pounds Brand A. 0.8 pounds Brand B
D. 2.3 pounds Brand A. 2.7 pounds Brand B

Answer 1

C. 4.2 pounds Brand A. 0.8 pounds Brand B

Explanation:

How much of each brand of coffee is needed to make 5 pounds that will cost

$6.75/pound?

Let the number of pounds for Brand A = x

Let the number of pounds for Brand B = y

Brand A coffee sells for $7/pound, while Brand B sells for $5.40/pound.

$7 × x + $5.40 × y = $6.75 × 5

7x + 5.40y = 33.75.......Equation 1

x + y = 5 .......Equation 2

x = 5 - y

7(5 - y)+ 5.40y = 33.75

35 - 7y + 5.40y = 33.75

35 - 33.75 = 7y - 5.40y

= 1.25 = 1.6y

y = 1.25/1.6

y = 0.78125 pounds.

Approximately to the nearest whole number, Brand B = 0.8 pounds.

x = 5 - y

x = 5 - 0.8 pounds

x = 4.2 pounds

Brand A = 4.2 pounds