**Concept:** **The question tests on the area of Rates(Time and Work)**

**Solution:**

Ram does 40% = 2/5th of the work in 12 days

To complete the work, time taken = 1∗12/(2/5) =30 days

The remaining work is 60% = 60 /100 = 3/5th of the work

Working together they finish 3/5th of the work in 12 days

Therefore to do the complete work = 1∗12/(3/5)= 20 days

Work done by Ram in 1 day = 1/30

Let Ravi take x days to finish the work. Work don by Ravi in 1 day = 1/x

1/30+1/x=1/20

1/x=1/20−1/30=3−2/60=1/60

Ravi takes 60 days to complete the work which is twice the time Ram takes

Ram is 100% more efficient than Ravi

Option B