```
Ans : 99/70
```

Solution:

```
next_num = (numerator + 2 * denominator) / (numerator + denominator)
(1 + 2 * 1) / (1 + 1) = 3/2
(3 + 2 * 2) / (3 + 2) = 7/5
(7 + 2 * 5) / (7 + 5) = 17/12
(17 + 2 * 12) / (17 + 12) = 41/29
(41 + 2 * 29) / (41 + 29) = 99/70
```