Question

Kelly blends coffee. She mixes brand A costing $6 per kilogram with brand B costing $8 per kilogram. How many kilograms of each brand does she have to mix to make 50 kg of coffee costing her $7.20 per kg?​

Answer 1

Step-by-step explanation:

Let

x

be the kg of coffee of brand A in the mix and

y

be the kg of coffee of brand B in the mix.

The total kg must be

50

.

x

+

y

=

50

The cost per kg of the mix must br

$

7.20

. For this, the total cost of the mix will be

6

x

+

8

y

, so the total cost per kg of the mix will be

6

x

+

8

y

50

.

6

x

+

8

y

50

=

7.20

Now that we have our two equations, we can solve.

6

x

+

8

y

=

7.20

⋅

50

6

x

+

8

y

=

360

From the first equation, we can multiply both sides by

6

to get:

6

x

+

6

y

=

300

Subtracting, we get:

2

y

=

60

y

=

30

Thus, we need

30

kg of brand B in our mix. This means that

50

−

30

=

20

kg will be of brand A.