l-length of the pic and w-width
18*15-LW - Sof the frame
LW - S of the pic
18/15=L/W --> W= 15L/18
according to the statement 18*15-LW=LW --> 18*15-L*15L/18=L*15L/18 --> L=9\sqrt{2}
A
18*15-LW - Sof the frame
LW - S of the pic
18/15=L/W --> W= 15L/18
according to the statement 18*15-LW=LW --> 18*15-L*15L/18=L*15L/18 --> L=9\sqrt{2}
A