Sylvia paid $4.20 for 2kg of sugar and 4 kg of flour. If 1 kg of sugar and 1 kg of flour cost $1.50, find the cost of 1 kg of flour.
cost of sugar --- $x per kg
cost of flour --- 1.5 - x per kg
2x + 4(1.5-x) = 4.2
solve for x
To find the cost of 1 kg of flour, we can use the given information and set up a system of equations.
Let the cost of 1 kg of sugar be 's' and the cost of 1 kg of flour be 'f'.
From the problem, we know that:
2 kg of sugar + 4 kg of flour = $4.20 ---(equation 1)
1 kg of sugar + 1 kg of flour = $1.50 ---(equation 2)
To solve this system of equations, we can use either the substitution method or the elimination method. Here, let's use the substitution method.
From equation 2, we can express the cost of 1 kg of sugar as:
s = $1.50 - f
Now substitute this value of s in equation 1:
2($1.50 - f) + 4f = $4.20
Expanding the equation, we have:
$3 - 2f + 4f = $4.20
Combining like terms, we get:
2f = $4.20 - $3
2f = $1.20
Finally, divide both sides of the equation by 2:
f = $1.20/2
f = $0.60
Therefore, the cost of 1 kg of flour is $0.60.