To solve this problem, we can use the concept of work rates. Let's assume Krish's work rate is 1 unit per day. Since Ram is half as efficient as Krish, his work rate would be 0.5 units per day.
Now, let's calculate how long it would take for Ram to complete the work alone. We can set up the equation:
Ram's work rate * Time taken = 1 (complete work)
0.5 * Time taken = 1
Time taken = 1 / 0.5
Time taken = 2 days
Therefore, it would take Ram 2 days to complete the work alone.
Now, let's calculate how long it would take for Ram and Krish to complete the work together. To find the combined work rate, we can add their individual work rates:
Combined work rate = Ram's work rate + Krish's work rate
Combined work rate = 0.5 + 1
Combined work rate = 1.5 units per day
Now, let's set up the equation for the combined work rate:
Combined work rate * Time taken = 1 (complete work)
1.5 * Time taken = 1
Time taken = 1 / 1.5
Time taken ≈ 0.67 days
Since the time taken cannot be a fraction of a day, we round it up to the nearest whole number, which is 1 day.
Therefore, Ram and Krish will take 1 day to complete the work together.
The correct answer is D) 8.