Differences are multiples of 4 starting from 4 ie., 5 + (4*1) = 9 9 + (4*2) = 17 17 + (4*3) = 29 29 + (4*4) = 45 45 + (4*5) = 65.
A=5 Next element =45+20 =65 because the difference between the each element as the series:4,8,12,16,20 etc.
65 is the correct answer as the difference in the series is 4,8,12,16,20 which makes 45 to65
The answer is 45 + 20 = 65
+4 +8 +12 +16 +20.. 65!
65 is the answer