Given:
The average of 8 consecutive even numbers is 43
Calculation:
let the 8 consecutive even numbers be x , x+2 , x+4 , x+6 , x+8 , x+10 , x+12 , x+14
For a series of consecutive terms middle term will be the average of the series
Hence, Average of x+6 and x+8 will be the average of 8 consecutive even numbers
x + 6 + x + 8 / 2 = 43
x + 7 = 43
x = 36
The 8 consecutive even numbers be 36 , 38 , 40 , 42 , 44 , 46 , 48 , 50
if the next consecutive even number 52 also considered then,
The 9 consecutive even numbers series is 36 , 38 , 40 , 42 , 44 , 46 , 48 , 50 , 52
The Average of 9 consecutive even numbers is middle term of the series
So, the middle term is 44
The new average is 44
Answer is 44.

Alternate MethodGiven:
The average of 8 consecutive even numbers is 43
Formula used:
Average = Number of TermsTotal Sum
Calculation:
let the 8 consecutive even numbers be x , x+2 , x+4 , x+6 , x+8 , x+10 , x+12 , x+14
Average = 8x+x+2+x+4+x+6+x+8+x+10+x+12+x+14
43 = 8x + 56 / 8
43 = x + 7
x = 36
The 8 consecutive even numbers be 36 , 38 , 40 , 42 , 44 , 46 , 48 , 50
if the next consecutive even number 52 also considered then,
The 9 consecutive even numbers series is 36 , 38 , 40 , 42 , 44 , 46 , 48 , 50 , 52
Average = 936+38+40+42+44+46+48+50+52
= 396 / 9
= 44
The new average is 44
Answer is 44.