Question by Lê Quốc Trần Anh - Discuss with MathYouLike

Lê Quốc Trần Anh Coordinator

03/01/2018 at 17:01

Three books and eight CDs cost twice as much as one book and five CDs. If one book and one CD cost $45, what is the cost of six books?

List of answers

Dao Trong Luan Coordinator 03/01/2018 at 17:34

Tell the books is a, the CD is b

=> \(3a+8b=2\left(a+5b\right)\) and a+b = $45

=> 3a + 8b = 2a + 10b

=> a = 2b

=> a+b = b+2b = 3b = $45 <=> b = $15

=> a = $15.2 = $30

=> 6a = $30.6 = $180

So the answer is $180
Lê Quốc Trần Anh selected this answer.
Asuna Yuuki 03/01/2018 at 20:05

Tell the books is a, the CD is b

=> $3 a + 8 b = 2 (a + 5 b)$ and a+b = $45

=> 3a + 8b = 2a + 10b

=> a = 2b

=> a+b = b+2b = 3b = $45 <=> b =$ 15

=> a = $15.2 = $30

=> 6a = $30.6 =$ 180

So the answer is $180
FA Liên Quân Garena 08/01/2018 at 21:49

Tell the books is a, the CD is b

=> 3a+8b=2(a+5b)

and a+b = $45

=> 3a + 8b = 2a + 10b

=> a = 2b

=> a+b = b+2b = 3b = 45<=>b=

15

=> a = $15.2 = $30

=> 6a = 30.6=

180

So the answer is $180

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