The right answer is Option A.
Step-by-step explanation:
Let,
x be the postcards
y be the large envelops
According to given statement;
14x+5y=12 Eqn 1
10x+15y=24.80 Eqn 2
Multiplying Eqn 1 by 3;
Subtracting Eqn 2 from Eqn 3;
Dividing both sides by 32
Putting x=0.35 in Eqn 1;
Dividing both sides by 5
Therefore, one large envelope costs $1.42
The right answer is Option A.
Keywords: linear equations, subtraction
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