Linear equation

Question

The number of books in a class library is 17 more than 3 times the number of students in the class. If 5 students are absent, each student can borrow exactly 4 books from the library. Find the no. Of students

Answer 1

Let :

B = # of books

S = # of students

From the word problem, you get the following equations

B = 17 + 3*S

B = (S - 5) * 4

Since both equations are the value of B, you can set them equal to each other...

B = 17 + 3*S = (S - 5) * 4

Now solve

17 + 3*S = (S - 5) * 4

17 + 3*S = 4S - 20

37 + 3*S = 4S

37 = S

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Always check your work!

17 + 3*S = (S - 5) * 4

17 + 3*37 = (37 - 5) * 4

17 + 111 = (32) * 4

128 = 128 CORRECT!