Question

In the following series of numbers, find out how many times 1, 3 and 7 have appeared together, 7 being in the middle and 1 and 3 on either side of 7.
2973173771331738571377173906

• A. 3
• B. 4
• C. 5
• D. More than 5

Answer 1

The correct option is A 3

$2973\underset{–}{173}77133\underset{–}{173}8571377\underset{–}{173}906$