<PRE><B>Question 52092</B>
Try this:
Let x = the length required to be covered and L = the length of a plank.
1) 3L = x-1 Multiply this by 4.
2) 4L = x+2 Multiply this by 3.

1a) 12L = 4x-4
2a) 12L = 3x+6 Subtract equation 2a) from 1a)
3) 0 = x-10 Add 10 to both sides.
x = 10 Substitute this into equations 1) and 2) and solve for L

3L = 10 - 1 = 9: L = 3
4L = 10 + 2 = 12: L = 3

The planks are 3 feet long.

Check:
3L = 9 = 10-1
4L = 12= 10+2</PRE>