Final answer:
The length of the shorter piece is 8.5 feet, and the length of the longer piece is 11.5 feet.
Step-by-step explanation:
To solve this problem, let's represent the lengths of the two pieces of the board as x and (x + 3), with x being the length of the shorter piece. The sum of the lengths of the two pieces should be equal to the total length of the board, which is 20 feet. So we can set up the equation: x + (x + 3) = 20. Simplifying this equation, we get 2x + 3 = 20. Subtracting 3 from both sides, we have 2x = 17. Finally, dividing both sides by 2, we find that x = 8.5 feet. Therefore, the length of the shorter piece is 8.5 feet, and the length of the longer piece is 8.5 + 3 = 11.5 feet.