10. Lily built an orange shelf and a brown shelf to hang in her
    room. The orange shelf is 5 feet 6 inches long. The brown
    shelf is twice as long. What is the length of the brown shelf?

To find the length of the brown shelf, we first need to convert the length of the orange shelf into inches. There are 12 inches in a foot, so 5 feet 6 inches is calculated as (5 x 12) + 6 = 60 + 6 = 66 inches. Since the brown shelf is twice as long as the orange shelf, we multiply 66 inches by 2, giving us 132 inches. Now, converting 132 inches back into feet, we find that it is 11 feet long (as 132 divided by 12 equals 11).

So, the length of the brown shelf is 11 feet!