Data Sufficiency (DS) | 16 horses can haul a load of lumber in 24 minutes. 12 horses started h

Answer is B.

Let h - time taken by single horse to load (in minutes)
m - time taken by single mule to load (in minutes)

Given: 16 horses -> 24 mins => time taken by single horse is (16 * 24) = 384 minutes
so amount of job completed by 1 horse in 1 min => 1/384
amount of job completed by 12 horse in 1 min => 12/384
amount of job completed by 12 horses in 14 min => (14 * 12/384) = 9/16

So before mules join (7/16) of work
...

---