Ryan bought 3 books and a magazine . he paid $30 and relieved $5 change if the magazine cost twice as much as each book, find the cost of the magazine.
explain in algebra only : )

 The required cost of the magazine is $10.

Step-by-step explanation:  Given that Ryan bought 3 books and a magazine. He paid $30 and relieved $5 change and the magazine cost twice as much as each book.

We are to find the cost of the magazine.

Let x and y represents the cost of a book and the magazine respectively.

Then, according to the given information, we have

and

Substituting the value of y from equation (ii) in equation (i), we get

and from equation (ii), we get

Thus, the required cost of the magazine is $10.

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this