Answer:
Step-by-step explanation:
You would add the number 3 every time you go through a set of ten numbers, until you hit the thirties. When you hit there, you're going to count every single number counted until you reach forty, answer;
1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
The digit 3 appears <em>14</em> times.