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Question
S1.
We take a more
detailed look at Simultaneous Equations which
follow a different system to solve. Simultaneous
Equations are problems which not only uses an 'x'
as an unknown. but will also feature a 'y'
unknown.
Below the
problem gives us two facts, and each contain 2
unknowns - an 'x' ('B' =number of burgers), and a
'y' ('F' =portions of french fries). We have kept
these as 'B' and 'F' so they can be more easily
identified.
A
man buys 2 Burgers and 3 portions of French Fries
for $12
Another man buys 1 Burger and 4 portions of French
Fries for $11
How
much are the burgers and how much are the french
fries?
For problems
like this we use Simultaneous Equations.
We write the 2
facts in algebraic form. (B=Burgers, F=French Fries
- I expect you got that)
(1)
2B + 3F = 12
(2)
..B
+ 4F = 11
We
observe that
fact (1) has 2B in it, and fact (2) has a 1B in it.
We double the fact (2) equation in order to get 2B
in BOTH equations, so that if we subtract (1) fact
from (2) fact THE 'B' COMPONENT WITH DISSAPEAR. The
aim is always to get a similar component in each
fact.
(Naturally in
other examples the multiplier will be
different)
(3)
..2B
+ 8F = 22
We now subreact
(1) from (3)
(3)
..2B
+ 8F = 22
(1) ..2B
+ 3F = 12
(4)..............
5F = 10
F =
$--
Click on the
answer below you believe is the correct
one
Answer
to question S1:
'A'
-
Burgers cost $4, French Fries cost
$1
'B'
-
Burgers
cost $5, French Fries cost $2
'C'
- Burgers
cost $4, French Fries cost $1.50
'D'
- Burgers
cost $3, French Fries cost $2
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