Find the length of each piece

Question

suppose the a board 20 feet long is cut into two pieces. Four times the length of the shorter piece is 4 feet less than three times the length of the longer piece. Find the length of each piece. 

Answer 1

s + l = 20 ------> s = 20 - l

4s = 3l  - 4

4(20 - l) = 3l - 4

80 - 4l = 3l - 4

7l = 84

l = 12

 

s = 20 - 12 = 8