the 250 cm board is cut into 5 pieces.
since three short pieces are of equal length, lets name each piece as 'x'
the longer ones are 15 cm longer than shorter ones so we can name them as 'x +15'
the sum of these pieces are 250
x + x + x + (x+15) + (x + 15) = 250
3x + 2x + 30 = 250
5x = 250 - 30
5x = 220
x = 44 cm
length of a short piece - 44 cm
length of long piece - 44 + 15 = 59 cm
