13, a, b, c are four distinct numbers and the HCF of each pair of numbers (13, a); (13, b); (13, c) is 13, where a, b, c are each less than 60 and a < b < c. What is the value of \(\frac{{{\rm{a}}\,{\rm{ + }}\,{\rm{c}}}}{{\rm{b}}}\)?
1
2
2
5
3
4.5
4
3.5