"8 Cakes and 3 Pies Cost 6.40"
"5 Cakess and 2 Pies cose £4.05"
WHich would be...
8x + 3y = 6.4
5x + 2y = 4.05
is this correct?
2007-12-17 01:25:29 · 22 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
yes
& to continue the solution
8x + 3y = 6.4 -----> mulyiply by 2
5x + 2y = 4.05 ------> multiply by 3
16x+6y=12.8
15x+6y=12.15
---------------(subtract)
x= 0.65
so 5*0.65 +2y=4.05
2y=4.05-3.25 = 0.8
y=0.4
2007-12-17 01:48:03 · answer #1 · answered by mbdwy 5 · 0⤊ 0⤋
let cakes = x
pies = y
8x + 3y = 6.4
5x + 2y = 4.05
from second equation we find the value of y
5x + 2y = 4.05
2y = 4.05 - 5x
y = (4.05 - 5x) / 2
put the value of y in first equation
8x + 3((4.05 - 5x) / 2) = 6.4
8x + (12.15 - 15x) / 2 = 6.4
8x + 12.15/2 - 15x/2 = 6.4
8x -15x / 2 = 6.4 - 12.15 / 2
16x / 2 - 15x / 2 = 12.8 / 2 - 12.15 / 2
((16 -15)x) / 2 = (12.8 - 12.15) / 2
x / 2 = 0.65 / 2
x = 0.65
put this new value of x in any equation (say first) to find the value of y
8(0.65) + 3y = 6.4
5.2 + 3y = 6.4
3y = 1.2
y = 0.4
therefor
x = cake = £0.65
y = pie = £0.4
2007-12-18 01:42:32 · answer #2 · answered by Rayan Ghazi Ahmed 4 · 0⤊ 0⤋
yes that is the way you set it up.
next you would just multiply both of the equations to have the same number as each other.
ex.
(2)8x + 3y = 6.4(2)
(-3)5x + 2y = 4.05(-3)
16x + 6y = 12.8
-15x - 6y = -12.15
x = .65
hope you can figure out y
2007-12-17 01:32:02 · answer #3 · answered by yeayeayea 3 · 0⤊ 0⤋
Yes that is correct Now just work it out to check it
2007-12-17 01:36:08 · answer #4 · answered by softballsoccerq 2 · 0⤊ 0⤋
yes, in these equations x represents the price of cakes and y represents the price of pies
2007-12-17 01:28:56 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Looks good
2007-12-17 01:39:16 · answer #6 · answered by Andrea M 2 · 0⤊ 0⤋
Yes it is correct
2007-12-17 01:28:23 · answer #7 · answered by ○G 2 · 0⤊ 0⤋
Den, you can't have dollars and pounds unless you are running two separate equations. If you are then okay.
2007-12-17 01:29:43 · answer #8 · answered by Ken L 3 · 0⤊ 0⤋
yes
2007-12-17 01:35:47 · answer #9 · answered by dustinknip 2 · 0⤊ 0⤋
yes.
then you can solve the 2 equations by substitution, or by elimination.
good luck!
2007-12-17 01:29:45 · answer #10 · answered by Anonymous · 0⤊ 0⤋