Sally bought three chocolate bars and a pack of gum and paid $1.75. Jake bought two chocolate bars and four packs of gum and paid $2.00. Find the cost of a chocolate bar and the cost of a pack of gum.
2006-12-17 14:11:50 · 7 answers · asked by pitabelle74 2 in Education & Reference ➔ Homework Help
Let x = Chocolate bars
Let y = Gum
3x + y = $1.75
2x + 4y = $2.00
Multiply the first equation by -4.
-12x -4y = $-7.00
Now add this to the second equation
2x + 4y = $2.00
See how the 4y's will now cancel?? That's why we multiplied by -4.
-10x = -$5.00
x = .50
So, one chocolate bar is 50 cents.
Now plug back into an equation to get the pack of gum.
3x + y = $1.75
y = 25 cents.
Chocolate 50 cents
Gum 25 cents
2006-12-17 14:16:55 · answer #1 · answered by mysstere 5 · 2⤊ 0⤋
a pack of gum costs 25 cents and the chocolates bars cost 50 cents
2006-12-17 14:14:17 · answer #2 · answered by Sarah W 1 · 0⤊ 1⤋
The chocolate bars cost .50 cents and the gum.25 cents.
2006-12-17 14:17:52 · answer #3 · answered by Ted 6 · 0⤊ 1⤋
chocolate bars are 50 cents and gum is 25 cents
As so: 3 X 0.50 = 1.50 + 0.25 = 1.75
As so 2 X 0.50 = 1.00 + (4 X 0.25) =2.00
2006-12-17 14:16:29 · answer #4 · answered by jojot001 2 · 0⤊ 1⤋
c=chocolate bar
p=pack of gum
3c+p=1.75, therefore
(1)p=1.75-3c
(2)2c+4p=2
sub equation (1) into equation (2):
2c+4(1.75-3c)=2
2c+7-12c=2
-10c=-5
c=0.5 - (chocolate bars are $0.50 each)
sub c into equation (1)
p=1.75-3(0.5)
p=0.25 - (packs of gum are $0.25 each)
2006-12-17 14:18:03 · answer #5 · answered by Onyx Blackman 3 · 1⤊ 0⤋
Solve:
3C + G = 1.75
2C + 4G = 2.00
Use either substitution or elimination.
By substitution, the first equation would be:
G = -3C + 1.75
Substitute that into the other equation:
2C + 4(-3C + 1.75) = 2.00
Once you get "C", substitute it back into the "G = " equation.
2006-12-17 14:14:25 · answer #6 · answered by Pi-Guy 2 · 1⤊ 1⤋
That sucks to have to answer that one.
My avatar sorta looks like yours =D
2006-12-17 14:13:29 · answer #7 · answered by Gia 2 · 0⤊ 2⤋