Question 10949
Let the third part be of length l

Then the length of the 2 unequal parts which are greater than the third part by 5 cms is l+5

Total lenght = 31
l+5+l+5+l=31
3l+10=31
Subtracting 10 on both sides
3l=31-10
3l=21
Dividing by 3 throughout
l=7
And so the other parts are of length 12cms each.