Given that original lenght of the board before cut [tex] = \frac{7}{10} [/tex]meter
Lenght of the board that is left after cutting from the original piece by Hernan [tex] = \frac{3}{10} [/tex]meter
Now we have to find the lenght of the piece which is cut.
To find that we just need to subtract smaller piece from larger piece
Required Length [tex] = \frac{7}{10}-\frac{3}{10} [/tex]meter
Required Length [tex] = \frac{7-3}{10} [/tex]meter
Required Length[tex] = \frac{4}{10} [/tex]meter
reduce the fraction
Required Length [tex] = \frac{2}{5} [/tex]meter
Hence final answer is [tex] \frac{2}{5} [/tex] meter.
