Two customers went to a post office to buy postcards and large envelopes. Each postcard
costs the same amount, and each large envelope costs the same amount.
The first customer paid $12 for 14 postcards and 5 large envelopes.
The second customer paid $24.80 for 10 postcards and 15 large envelopes.
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What was the cost in dollars of each large envelope?
A $1.42 c $1.15
B $0.35 D $0.63

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absor201 absor201 · Answer 1 · 2019-12-07T13:47:54+01:00

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;

[tex]3(14x+5y=12)\\42x+15y=36\ \ \ Eqn \ 3[/tex]

Subtracting Eqn 2 from Eqn 3;

[tex](42x+15y)-(10x+15y)=36-24.80\\42x+15y-10x-15y=11.20\\32x=11.20\\[/tex]

Dividing both sides by 32

[tex]\frac{32x}{32}=\frac{11.20}{32}\\x=0.35[/tex]

Putting x=0.35 in Eqn 1;

[tex]14(0.35)+5y=12\\4.90+5y=12\\5y=12-4.90\\5y=7.10[/tex]

Dividing both sides by 5

[tex]\frac{5y}{5}=\frac{7.10}{5}\\y=1.42[/tex]

Therefore, one large envelope costs $1.42

The right answer is Option A.

Keywords: linear equations, subtraction

Learn more about linear equations at:

#LearnwithBrainly

alphawolf3107 alphawolf3107 · Answer 2 · 2021-04-30T21:37:51+02:00

Answer: A. $1.42

Step-by-step explanation: I did it on the test and got it right!

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