Let's assume that the original length of the piece of board is L.
Now you cut two pieces that are 3.4 ft long, so the remaining piece of board is:
L - 3.4ft - 3.4ft = L - 6.8ft long.
Now we know that the remaining must be 2.35 times longer than the pieces of 3.4 ft, then we have the equation:
( L - 6.8ft) = 2.35×3.4ft
solving that for L we get:
L = 14.79ft
Rounding to the nearest tenth, we get:
L = 14.8ft
You should buy a piece of board that is 14.8 feet long.
If you want to learn more, you can read:
brainly.com/question/22293035