math
posted by Katherine .
kyle had 36 books in hislocker. some were library books, some were textbooks, and the rest were telophone books. the number of library books and textbooks combined equal twice the number of textbooks. the number of textbooks and telephone books combined equals three times the number of library books. how many of each type of book were in kyle's locker??
please help me....i need a chart or a rule to show me how u got it....please

Do it this way
a=library books
b=textbooks
c=telephone books
You know a + b + c = 36
You know that a + b = 2b (library books plus textbooks equals twice number of textbooks)
You know that b + c = 3a (textbooks plus telephone books equals three times number of library books)
Take equation #2 a+b=2b
Subtract b from each side
a=b The number of library books equals the number of textbooks
Take equation #3 b+c=3a Substitute a for b since you know now from equation #2 that a=b Now you have a+c=3a
Subtract a from each side c=2a
Now, go to equation #1 a+b+c=36
You know a=b
You know c=2a
substitute
a + a + 2a = 36
Combine like terms and divide
4a = 36 a= 9
Again, you know a = b and c= 2a therefore a=9, b=9, c=18
9 library books
9 text books
18 telephone books
Respond to this Question
Similar Questions

algebra
John has 36 books in his locker. He has text books,library books, and telephone books. How many books of each kind does he have if: lib + tel= 2x text books and text + tel = 3x lib books I think it'd be easier to let T,L and B denote … 
math
kyle had 36 books in hislocker. some were library books, some were textbooks, and the rest were telophone books. the number of library books and textbooks combined equal twice the number of textbooks. the number of textbooks and telephone … 
math
kyle had 36 books in hislocker. some were library books, some were textbooks, and the rest were telophone books. the number of library books and textbooks combined equal twice the number of textbooks. the number of textbooks and telephone … 
Math, Please help :/
Kyle had 36 books in his locker. Some were library books, some were textbooks, and the rest were telephone books. The number of library books and telephone books combined equals 3 times the number of library books.How many of each … 
math
MEghan had 36 books in her locker. Some were library books, text books and the rest were telephone books. THe number of library books and phone books combined equals twice the number of text books. The number of text books and telephone … 
math
the library has a total collection of 2630 books. the number of nonfiction books is 240 fewer than the number of fiction books but 190 more than the number of picture books. how many books of each type are there in the library? 
math
the library has a total collection of 2630 books. the number of nonfiction books is 240 fewer than the number of fiction books but 190 more than the number of picture books. how many books of each type are there in the library? 
math
the library has a total collection of 2630 books. the number of nonfiction books is 240 fewer than the number of fiction books but 190 more than the number of picture books. how many books of each type are there in the library? 
algebra
A textbook store sold a combined total of 205history and math textbooks in a week. The number of history textbooks sold was 87more than the number of math textbooks sold. How many textbooks of each type were sold? 
Stats
You have many old textbooks in your apartment. You have 6 math books, 7 econ, and 4 accounting. Assume that each textbook is different than the other. A) What is the probability that the last book is one of the economic textbooks?