Sue has red apples worth 2.30$ per pound and green apples worth 1.90$ a pound How many pounds of each should she mix to get a mixture of 20 pounds worth 2.06$ per pound?

2 Answers
Oct 22, 2017

8 pounds of red apples
12 pounds of green apples

Explanation:

The "pounds" is the variable with different cost factors.
The total package of 20 pounds will have a value of
20×2.06=41.20

The components of this value are from the two apple types:
41.20=2.30×Wr+1.90×Wg
Wr+Wg=20 ; Wr=20Wg

Substitute this into the overall equation:
41.20=2.30×(20Wg)+1.90×Wg

Solve for Wg:
41.20=462.30×Wg+1.90×Wg
4.80=0.4×Wg ; Wg=12

Solve for Wr:
Wr=20Wg ; Wr=2012=8

CHECK:
41.20=2.30×Wr+1.90×Wg
41.20=2.30×8+1.90×12
41.20=18.40+22.80=41.20 CORRECT!

Oct 22, 2017

Red apples =8 pounds
Green apples =12 pounds

Explanation:

Let Red Apples, bought be x pounds
Let Green Apples, bought be y pounds

Then-

x+y=20 in terms of quantity --------------- (1)
(x×2.30)+(y×1.90)=20×2.06 in terms of money

2.3x+1.9y=41.2 ------------ (2)

Solve equation (1) for x

x=20y

Substitute x=20y in equation (2)

2.3(20y)+1.9y=41.2
462.3y+1.9y=41.2
0.4y=41.246=4.8
y=4.80.4=12

y=12
Substitute y=12 in equation (1)

x+12=20
x=2012=8
x=8

Red apples =8 pounds
Green apples =12 pounds