The average of 21 numbers is 44. The average of first 11 numbers is 48 and that of last 11 numbers is 42. If $$11^{th}$$ number is excluded, What is the average of the remaining numbers?

given that the average of 21 numbers be 44

so sum of the numbers is 924

given that average of first 11 numbers is 48

so its sum= 528

 Also given that average of last 11 numbers is 42

so it sum =462

excluding 11th number we need to find the average of remaining numbers

so 528-462=66

subtract this value from total sum

924-66=858

now finding the average

858/20=42.9  (20,since we are excluding one digit)

hence answer is option d