The cost , in dollars, for 3 pounds of oranges is 1.8
Solution:
Given that Monica paid 3.20 for 2 pounds of apples and 2 pounds of oranges
Sarah paid 4.40 for 2 pounds of apples and 4 pounds of oranges.
Let the cost of orange per pound = x
Let the cost of apple per pound = y
Therefore, we can frame an equation as follows for Monica and Sarah:
In Monica’s case:
2x + 2y = 3.20
Hence x + y = 1.6 ---- eqn 1
In Sarah’s case:
4x + 2y = 4.40
Hence 2x + y = 2.2
y = 2.2 -2x – eqn 2
Substitute eqn 2 in eqn 1 we get,
x + 2.2 -2x = 1.6
-x = 1.6-2.2 = -0.6
x = 0.6
Substituting the value of “x” in eqn 2 we get the value of “y” as 1
Thus the cost of orange per pound is 0.6
Therefore, cost of 3 pounds of oranges = 3 × 0.6 = 1.8