Need help baaaaaaaaad

[passionflower_40]

Write a system of two equations in two unknowns for this problem.

Books and Magazines. At Gwen's garage sale, all books were one price, and all magazines were another price. Harriet bought four books and three magazines for $1.45, and June bought two books and five magazines for $1.25. What was the priceof a book and what was the price of a magazine? (Can some help me pleaseeeeeee)

 

[tkhunny]

I'll get you started.

"What was the priceof a book?"

B = Price of One Book

"What was the price of a magazine?"

M = Price of One Magazine

What's next?

 

[passionflower_40]

would it be

4b+3m=1.45

2b+5m =1.25

please let me know I am on the right track.

 

[passionflower_40]

4b+3m=1.45

2b+5m =1.25

because 12 is the least common multiple of 4 and 3 would I multiply the first equation by -3 and the second by 4?

 

[Unco]

What would happen if you did that?

Remember that you want to cancel out just the b's (or just the m's). What would you multiply the equations by to cancel out the b's?

 

[Denis]

4b+3m=1.45
2b+5m =1.25

"Go forth and multiply" 2nd equation by -2; then add up the 2 equations;
what does that do for you?
4b + 3m = 1.45
-4b -10m = -2.50

Make it easier still by changing all signs:
-4b - 3m = -1.45
4b +10m = 2.50

So adding those gives: 7m = 1.05

Can you take over?

 

[passionflower_40]

Well this is my answer I worked out can you please check

4b+3m=1.45
2b+5m =1.25

-3(4b+3m) = -3(1.45)
4(2b + 5) = 4(1.25)

-12b – 9m = -435
8b + 13m = 5

-m = -0.65
m = 0.65

4b + 3(0.65) = 1.45
4b + 1.95 = 1.45
4b = 1.95
b = 0.487 or 0.49


So, the price of a book was $0.49 and the price of a magazine was
$0.65.

 

[Gene]

Reread Denis's last post and look at what he did.

Check your answer by substituting in the first equation.
4b+3m = 1.45
4*.49+3*.65 =
1.96+1.95 =
3.91 ?=? 1.45
Nope!
----------------
Gene

 

[tkhunny]

would it be

4b+3m=1.45

2b+5m =1.25

please let me know I am on the right track.

Almost. If you are using my definitions, you should use the same variables. Uppercase and lowercase generally are not considered the same thing. If you are using your own definitions, you should write them out clearly.