A rectangular picture is 10 cm longer than it is wide. It is mounted in a frame 1.5 cm wide on all four sides. The area of just the frame is 399 sq. cm. Find the demensions of the print.

Answer 1

If W is the width of the print, W+10 is the length. The frame can be considered as 2 pairs of rectangles, one pair of which are each W+3 by 1.5 and the other pair each W+13 by 1.5. Thus:

2((W+3)*1.5) + 2((W+13)*1.5) = 399 -> 3W+9+3W+39 = 399 -> 6W+48 = 399 -> 6W = 351 -> W = 58.5

So, the picture is 68.5 by 58.5 cm