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kay4451
19.12.2019 •
Mathematics
Mary needs to send out some letters and postcards. she went online at the united states postal service webpage and found out that it cost 45 cents to mail a letter and 35 cents to mail a postcard. mary wrote to 15 people and the cost of postage was $6.15. if it cost 35 cents to mail a postcard and 49 cents to mail a letter, how many letters and how many postcards did he send?
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Ответ:
6 postcards and 9 letters
Step-by-step explanation:
First we label what we are looking for
Label number of postcard sent as x
Label number of letter sent as y
The we know Mary wrote to 15people, either as postcard or letter, so from this we make an equation
x + y = 15 (1)
The we know the amount Mary used to send all this is $6.15 which is also 615 cents
Then we know sending one postcard is 35cents, and we labeled number of postcards to be x
So total amount used for postcard will be 35x
And we know sending one letter is 45 cents, and we labeled number of letters to be y
So total amount used for letter will be 45y, so adding all this will be equals to the total amount used which is given as $6.15 also 615 cents, so making another equation
35x + 45y = 615 (2)
Solving the two simultaneously equations
x + y = 15 (1)
35x + 45y = 615 (2)
So we make y the subject of formula in (1)
y = 15 - x (3)
So we put (3) in (2)
Anywhere we see y, we put 15-x
35x + 45(15-x) = 615
35x + 675 -45x = 615
35x - 45x = 615 - 675
-10x = -60
divide both sides by -10
x = 6
So therefore, number of postcards is 6
Then we put x = 6 in (3)
y = 15 - x
y = 15 - 6
y = 9
So therefore number of letters is 9
Ответ:
Step-by-step explanation:
To find the lengths of the enlarged triangle, we would find the scale factor from the given length
22.5/5 = 4.5
So to find the other sides you would multiply 3 and 6 by 4.5
3 * 4.5 = 13.5
6 * 4.5 = 27
So all 3 lengths of the triangle are 22.5, 13.5, and 27
To find the perimeter you add all
22.5 + 13.5 + 27 = 63
Your answer is 63