Hi Sushil,
Yes, you should use a repeating group node with a question field underneath it and a default value on a totals field (above the repeating group) that calculates the total number of questions answered. You can use the count function that is built into InfoPath with a condition check inside to see if an answer was set.
To use a repeating group, you will have to add multiple rows and question values to the default values dialog.
Here's an example xpath that calculates count for all fields in your form:
count((//*[not(*)] | //@*)[not(name() =
"xml:lang")][.
!= ''])