Aptitude Hack#27(22-3-19)

Question:
A can lay railway track between two given stations in 16days and B can do the Same job in 12 days. With the help of C, they did the job in 4 days only. Then, C alone can do the job in:
A. 12 days
B. 11 days
C.48/5 days
D.10 days

Answer: C) 48/5 days

Explanation:

Method 1

(A+B+C)'s 1 day's Work=1/4
A's 1 day's work = 1/16
B's 1 day's work = 1/12
C's 1 day's work = 1/4 -(1/16 + 1/12 )
                    = 5/48
 So, C alone can do the work in 48/5 days
   
 Method 2

 Lcm (4,16,12) = 48
(A+B+C)'s 1 day's Work= 12 units
A's 1 day's work = 3 units
B's 1 day's work = 4 units
C's 1 day's work = 12 -(3+4) = 5 units
So, C alone can do the work in 48/5 days