Sergio had 8 colored pencils. He bought 3 more boxes of colored pencils. Sergio now has 35 colored pencils. If each box had the same number of pencils, how many pencils were in each box?
Solution
Number of pencils Sergio had + number of pencils purchased is equal to number of pencils he has now.
Let p be the number of pencils in each box
Let 8 be the number of pencils Sergio had
Let 35 be the number of pencils Sergio has now
Number of pencils purchased = 3 × p
Number of pencils purchased = 3p
Number of pencils Sergio had + number of pencils purchased is equal to number of pencils he has now.
The statement above gives the following equation
8 + 3p = 35
8 - 8 + 3p = 35 - 8
0 + 3p = 35 - 8
3p = 35 - 8
3p = 27
Divide both sides by 3
3p/3 = 27/3
p = 9
There are 9 pencils in each box