Question

Carl has three lengths of cable,

Answer 1

Lowest common denominator for 3,4,6 is 12

5/6 = 10/12
1/4 = 3/12
2/3 = 8/12

a)
10/12 + 3/12 = 13/12 = 1 1/12
So you need to use first and second cables

b)
3/12 + 8/12 = 11/12
To reach 1 yard Carl need 1/12 yard cable