Question

X works twice as fast as Y. If Y can complete a job alone in 12 days, then in how many days can X and Y together finish the job?

Answer 1

x = 2y

so,

y = 12 days

x = 6 days

total unit of work = 12

for l day,

x = 2 , y= 1

so,

x+y = 2+1 = 3unit = 1day

1 unit = 1/3

12 unit = 12/3

= 4 days