Answer:
10¹/₆ feet is less than 11 feet board, it's enough for both shelves
Step-by-step explanation:
First shelf is to measure = 4³/₄ feet
Second shelf is to measure = 5⁵/₁₂ feet
Total length of available board = 11 feet
Hence length of 1st and 2nd shelves are added to determine if its less than or equal to 11 feet
Length of 1st and 2nd shelves = 4³/₄ + 5⁵/₁₂ = 122/12 feet = 10¹/₆ feet
10¹/₆ feet is less than 11 feet board, it's enough for both shelves