Sachin has a certain average for 11 innings. In the 12th innings he scores 120 runs and thereby increases his average by 5 runs, his new average is:

Let's solve this step by step:

Step 1: Let's assume the average of Sachin's scores for the first 11 innings is 'x' runs.

Step 2: Therefore, the total runs scored in the first 11 innings would be 11x.

Step 3: In the 12th innings, Sachin scores 120 runs. So, the total runs scored after 12 innings would be 11x + 120.

Step 4: It's given that this score increases his average by 5 runs. So, the new average after 12 innings is 'x + 5'.

Step 5: The average is the total runs scored divided by the number of innings. So, we can set up the equation: (11x + 120) / 12 = x + 5.

Step 6: Solving this equation, we get: 11x + 120 = 12x + 60.

Step 7: Simplifying, we get: x = 60.

So, Sachin's new average after the 12th innings is 60 + 5 = 65 runs.