Delhi Police Constable Exam Model Paper 1

From the given data
We can write 4 at unit place of 4, 14, 24, 34, 44, 54 = 4 is 7 times
Also we can write at ten’s place 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 = 4 is 11 times
Total number of 4 = 11 + 7 = 18
But we count 44 two time, So
∴ Total 4 = 18 - 2 = 16
Mistake point:
Here, we have to count 44 twice as 4 is coming two times in 44.