MATHEMATICS MIDDLE SCHOOL

David bought 3 dvds and 4 books for $40 at a yard sale. Anna bought 1 dvd and 6 books for $18. How much did each dvd and book cost?

Answers

Answer 1
Answer:

Answer: d=$12, b=$1

d represents DVDs

b represets books

Step-by-step explanation:

Whenever you have 2 examples of 2 different things (such as books and dvds), make a systems of equations.

Step 1: Write a system of equations

3d+4b=  40

d+6b= 18

Step 2: Eliminate any letter. I'll just choose d.

To elimiate d, you have to make them both equal to the biggest d variable. In other words, make both d terms equal to 3d. To do this, miultiply the 2nd equation by 3, and keep the 1st one the same.

3d+4b=40

3d+18b= 54

Now, elimiate d, by doing 3d-3d= 0. Now use subtraction to solve for b since we used this to get 3 and 3 to 0.

4b-18b=40-54

-14b= -14

b= -14÷-14

b= 1

Each book costs 1 dollar.

Step 3: Plug in b=1 to find how much each dvd costs (plug into any equation)

3d+4b=40

3d+4(1)=40

3d+4=40

3d=40-4

3d=36

d=36÷3

d=12

Each dvd is $12

Step 4:  Checks--plug d=12 and b=1 into any equation

3d+4b=40

3(12)+4(1)=40

36+4=40

40=40

It's correct ✅

Also i know this was answered really late but id appreciate if i could get brainliest as i worked pretty hard for this :) Hope i could help the best i could :D

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Answers

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Answers

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Answers

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Answers

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Answers

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Answers

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