The DogHound book company is shipping a load of books to a library in Minnesota. If each student takes 4 books from the load, there will be 20 books left. If 3 students don't take books, and all the other students take 5 books each, then there won't be any books left. How many books are in the load?
2006-11-28 07:52:25 · 6 answers · asked by freddy197120032003 3 in Science & Mathematics ➔ Other - Science
There are 160 books.
You need to solve following equation (where students = x and books = y):
4x+20 = y
5(x-3) = y
which gives x = 35 and y = 160
2006-11-28 08:14:05 · answer #1 · answered by Jigyasu Prani 6 · 1⤊ 0⤋
A
Construct two equations containing the number of books (let it be "y") and the number of students (let it be "x"):
(1) y = 5(x-3)
(2) y = 4x+20
B
Construct the subtraction of the equations (1) and (2) (which is equal with zero!) to drop away one of the variables:
5(x-3) - (4x+20) = 0
C
Step B gives you x = 35 which is the number of students. Set this value in one or another of the equations (1) or (2) to have the final result y = 160 which is the number of the books.
D
If you would like to be sure about your result, you can check it by setting the value of x into the other equation (especially if it concerns more complicated equations!) . At last, check that your answer contains the number of books (which was asked), not the number of students...
2006-11-28 19:02:03 · answer #2 · answered by silberstein_9 3 · 0⤊ 0⤋
Let number of students be x and number of books be y.
4x + 20 = y
5(x - 3) = y
From the above equations,
4x + 20 = 5(x - 3)
4x + 20 = 5x - 15
20 + 15 = 5x - 4x
35 = x
Number of books = y = 4x + 20 = 4(35) + 20 = 160 books
2006-11-28 10:16:58 · answer #3 · answered by Kemmy 6 · 0⤊ 0⤋
Ermmmm, algebra was never my strong point...about 216?...;
2006-11-28 08:22:56 · answer #4 · answered by huggz 7 · 0⤊ 0⤋
lots
2006-11-28 22:02:43 · answer #5 · answered by Tipsy Dipsy 2 · 0⤊ 0⤋
one hundred and sixty...............
2006-11-28 08:36:35 · answer #6 · answered by justice 2 · 0⤊ 0⤋