4)
Ben, Joe and Alex bought flowers for their girlfriends at the same store.
Ben bought 5 roses, 8 daisies, and 2 carnations for $14.50. Alex bought
3 roses, 12 daisies, and 1 carnation for $14.00. Joe bought 10 roses, 1 daisy
and 3 carnations for $17.25. How much was one rose and one carnation?
rose:
carnation:

Respuesta :

Answer:

1 rose cost $1.5

1 carnation cost $0.5

Step-by-step explanation:

Let the price for one rose be r, price for one daisies be d and the price for one carnation be c

For Ben;

5r + 8d + 2c = 14.5

For Alex

3r + 12d + c = 14

For Joe

10r + d + 3c = 17.25

From equation iii;

d = 17.25- 10r - 3c

Insert this into the first two equations;

5r + 8(17.25-10r-3c) + 2c = 14.5

5r + 138 - 80r -24c + 2c = 14.5

-75r -22c = -123.5

Thus;

75r + 22c = 123.5

Insert the formula for d in the second equation;

3r + 12(17.25-10r-3c) + c = 14

3r + 207 - 120r -36c + c = 14

-117r-35c = 14-207

117r + 35c = 193

So we have two equations to solve simultaneously;

75r + 22c = 123.5

117r + 35c = 193

Multiply first equation by 35 and second by 22

2625r + 770c = 4322.5

2574r + 780c = 4246

Subtract second from first

51r = 76.5

r = 76.5/51

r = 1.5

Insert this in the equation below;

75r + 22c = 123.5

75(1.5) + 22c = 123.5

112.5 + 22c = 123.5

22c = 123.5-112.5

22c = 11

c = 11/22

c = 0.5