how many boards did the carpenter start with?

Question

 A carpenter has several boards of equal length. He cuts 3/5 of each board. After cutting the boards, the carpenter notices that he has enough pieces left over to make up the same length as 4 of the original boards. How many boards did the carpenter start with?

Answer 1

Hi Misti,

 

Let X = the number of boards each with a length of L

 

The original number of board lengths minus 3/5 of the board lengths leaves 4 board lengths:

 

XL - 3XL/5 = 4L

 

2XL/5 = 4L

 

20L = 2XL

 

20 = 2X

 

X = 10