Posted by es on .
A carpenter has several boards of equal length. He cuts 3/5 of each board. After cutting the boards the carpenter noticies he has enough pieces left to make up the same length as 4 origional boards. How many origional boards did he start with?
Someone told me the answer is 10 but I do not understand how they got it. I would like to know how to do the question, so can you explain the steps.
Thanks

4th grade math 
Sam,
We know each board is divided into 5 pieces, so the total number of pieces can be represented by 5x. Threefifths of each board is taken away and 2/5 is left. That's 2/5 of the total number of pieces...2/5(5x). The leftover pieces equal the total length of four boards from the original number of boards. The total length of four boards is 4 times 5 pieces. So here's the equation to solve:
2/5(5x)=20 the 5's cancel
2x=20
x=10
He started with 10 boards. 
4th grade math 
Anonymous,
1111111111

4th grade math 
Mia,
3/5 is taken away 2 is left

4th grade math 
Mia,
3/5 is taken away 2 is left that is my answer
from mia igoe 
4th grade math 
Jeremiah Estinvil,
Okay the answer should be 10 but I don't understand how Sam got 10. I Need an easier way to understand.( :/ )

4th grade math 
Jeremiah Estinvil,
Okay the answer should be 10 but I don't understand how Sam got 10. I Need an easier way to understand.( :I )

4th grade math 
Anonymous,
10

4th grade math 
Merline,
The answer is 2 whole boards and 2/5 of 1 because the thing says 4 of the oringal boards so add 3/5 4 times which gives u 12/5 which is an improper fraction and if make into a mix number it will be 2 2/5 so i check my work by drawing 2 boxes divide it into fifths shade in 3 then u have 2 left so to the other one u circle the 2 from the other box and 1 from this box and leaves u with 4 so take 3 shade in of that and have 1 left over then go to the next box circle the 1 from the other box then with the 2 from this box and he has 3 left because each boqrd was cut into 3 so like the question he has enough boards to make 1 more fence