1) Gathering the data
1 board = 6 yrds long
1 switch plate = 1/3 ft (length)
2) Let's set proportions to solve this problem:
1 foot ----------------------3/9 yards
1/3 ------------------------- x
x = 1/3 *3/9
x=3/27
x=1/9 yard
2) Since one light switch is 1/3 foot, then with a board 6 yards long:
We can divide the 6 yards by 1/9
3) So with a board 6 yards long we can make 54 light switch