In the following series of numbers, howmany 1, 3, 7 have appeared together. 7 being in middle and 1, 3 on either side of ??
2 9 7 3 1 7 3 7 7 1 3 3 1 7 3 8 5 7 1 3 7 7 1 7 3 9 0 6
Answer: C
3 1 7 3 7
3 1 7 3 8
7 1 7 3 9
At these places 1, 7, 3 appeared together